chapter- 7 reservoir -...

Chapter- 7Reservoir

7.0 General

Building reservoirs, either big or small, on rivers and streamsfacilitate conservation, management and development of water resources inour country in a big way. The spatial and temporal variations in rainfall andconsequent seasonal variations in stream flows necessitate creation ofreservoirs to obliterate the gap between the demand for water andavailability of flows in the respective time periods in the streams. Waterstored in a reservoir provides a buffer against water scarcity when rainfall isscanty. Reservoir is a source for renewable energy generation which ischeap and environment friendly. And also, water supplies to the needy areascould be delivered by gravity from the reservoirs which is very economical.Therefore, creation of reservoirs across rivers/streams for storage of water isvital for conservation, better management and optimum development ofwater resources in our country.

The river basins viz. Par, Auranga, Ambica and Purna, from whichdiversion of water is proposed through the Par-Tapi-Narmada link canal,receive 95% of annual rainfall in four months i.e. from June to Septemberduring South-West monsoon season. The average monsoon run-off in Par,Auranga, Ambica and Purna rivers is about 90% of annual run-off. Duringnon-monsoon season there would be negligible flows or no flows at all insome months in these rivers. While flows are available in these rivers in alimited period in a year, the water requirement for various purposes, such as,irrigation, drinking and industrial, ecological etc. to be met by the link canalare spread throughout the year. Therefore, to bridge the gap between flowsavailability in these rivers at different time periods and demands to be metin the respective time periods through the link canal, building storagesacross these rivers is essential. Further, the rivers are flowing in deepchannels in Western Ghats and whereas the cultivable lands are lying atmuch higher elevations. For irrigating these lands by gravity, it is necessaryto raise the water levels of the rivers by constructing dams/weirs/barragesacross them. Accordingly, six dams and two barrages are proposed underthe link project for diversion of surplus waters of Par, Auranga, Ambica andPurna rivers to needy areas en-route and to take-over part Command Area of

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Narmada Main Canal of Sardar Sarovar Project (SSP). The six damsproposed under the link project are: Jheri, Paikhed, Chasmandva, Chikkar,Dabdar and Kelwan. The two barrages are proposed, one each at thedownstream of Paikhed and Chasmandva dams for diversion of the releasesfrom Paikhed and Chasmandva reservoirs into the link canal.

The Jheri dam is proposed across Par River near village ‘Jheri’ inPeint taluka of Nasik district of Maharashtra State. Paikhed dam isproposed across Nar River (a tributary of Par) near village ‘Paikhed’ inDharampur taluka of Valsad district of Gujarat State. It is proposed to divertsurplus waters from Jheri reservoir to Paikhed reservoir through 12.7 kmlong inter-connecting tunnel. The combined waters will be released throughthe Dam toe Power House of Paikhed dam into Nar river and tapped atPaikhed barrage, proposed at about 4.60 km downstream near village ‘NaniCoswadi’ of Dharampur taluka, and let into the Link Canal which off-takesfrom Paikhed barrage.

The Chasmandva dam is proposed across Tan River (a tributary ofAuranga) near village ‘Chasmandva’ in Dharampur taluka. The surpluswaters of Tan River released through the Dam toe Power House ofChasmandva dam will be tapped at Chasmandva barrage, proposed at about8.5 km downstream near village ‘Chandha Chikadi’ of Dharampur taluka,and will be diverted into the Link Canal by a Feeder Pipe line of about2.859 km long.

The Chikkar dam is proposed across Ambica River near village‘Chikkar’ in Ahwa taluka of The Dangs district in Gujarat State. The surpluswater of Ambica River will be diverted through a 14.342 km long FeederCanal into Dabdar reservoir after power generation at Chikkar dam toePower House. The Dabdar dam is proposed across Khapri River (a tributaryof Ambica) near village ‘Dabdar’ in Ahwa taluka of The Dangs district. Thecombined surplus flows of Ambica and Khapri Rivers will be diverted intothe Link Canal through a 12.258 km long Feeder Pipe line after powergeneration at Dabdar dam toe Power House.

The Kelwan dam is proposed across Purna River near villages‘Kelwan’ and ‘Kakarda’ in Ahwa taluka of The Dangs district. The surplus

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waters of Purna River will be fed in to the Link Canal through a 7.616 kmlong Feeder Pipe line after power generation at Kelwan dam toe PowerHouse. A Canal Power House is proposed across the Feeder Pipe line whereconsiderable drop in ground level is observed.

It is planned to drop the Link Canal in to the existing Ukai reservoiron the river Tapi and to take it off from the right bank. However, neither thestorage of Ukai reservoir nor the waters of Tapi River would be used underthe Par-Tapi- Narmada Link Canal project. But the Ukai reservoir will beused just as a ‘Level Crossing’ for diversion of water through the LinkCanal. The Link Canal crosses Narmada River downstream of SardarSarovar Project and finally out-falls in to Miyagam branch canal ofNarmada Main Canal at RD 16.70 km.

In addition to the Link Canal’s demands, the above reservoirs willalso meet downstream environmental needs; domestic, industrial andirrigation needs of the areas located at the periphery of these reservoirs. Thepower generation at these reservoirs is planned utilizing releases for linkcanal, environmental releases, committed downstream releases, spills, etc.

Considering the inflow pattern and water demands for variouspurposes at a particular time, socio-economic and environmental impact dueto submergence and keeping in view the techno-economic aspects, attempthas been made to fix the size of the proposed reservoirs.

The details on criteria adopted for fixation of various reservoir levels,sedimentation studies carried out, area of submergence etc. of Jheri,Paikhed, Chasmandva, Chikkar, Dabdar and Kelwan reservoirs and thedetails relevant to proposed barrages are presented in the followingparagraphs.

7.1. Jheri Reservoir7.1.1. Fixation of Storage and Reservoir Levels - Approach–Criteria

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The water availability studies at Jheri, Paikhed, Chasmandva,Chikkar, Dabdar and Kelwan dam sites have been carried out by theHydrological Studies Organisation, CWC, New Delhi as a part of“Hydrological Studies of Par-Tapi-Narmada Link Project”. The Gross andNet Annual Yields at Jheri dam site as per these studies are as given inTable: 7.1.

Table: 7.1 Gross and Net Annual Yields at Jheri Dam Site

S.No.

Details Annual Yield (MCM)Gross Net

1 100% Dependable yield 183 1742 75% Dependable yield 391 3713 50% Dependable yield 467 4464 Average yield 528 509

The net water availability at Jheri dam site has been worked out aftersubtracting all the consumptive upstream utilizations planned by States.Regeneration from major and medium irrigation projects has been taken as10 percent while the same has been ignored in case of minor irrigationprojects. The regeneration from domestic and industrial uses has beenconsidered as 80 percent of water diverted for the purpose. The net yieldseries generated at Jheri dam site for the period from 1975-76 to 2006-07 isat Annexure: 5.12 in Volume - II.

The reservoir simulation study has been carried out for estimating thelive storage capacity of the reservoir that would provide the required yield atspecified reliability. The discharge data is available for a period of 39 yearsfrom 1966 to 2004 at Nanivahiyal G and D site maintained by Governmentof Gujarat on Par River, which is located d/s of Jheri dam site. Rainfall –Runoff model has been developed using discharge data available atNanivahiyal G and D site and rainfall for the concurrent period. The flowdata of inconsistent years have been discarded while developing Rainfall-Runoff model. Using this Rainfall – Runoff model the gross yield series forthe period from 1975-76 to 2006-07 at Jheri dam site has been developed.The net yield series at the dam site has been generated by subtracting the netupstream consumptive use from the gross yield series and used forsimulation analysis.

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The simulation analysis has been done using Simulation Programdeveloped using c++. This programme also takes into account the differentreleases from Jheri reservoir: i) for local domestic and industrial waterdemand, ii) environmental and ecological requirements downstream ofproposed dam site, and iii) diversion to Paikhed reservoir for further transferto Par-Tapi-Narmada Link Canal. The result of this analysis is at Appendix5.5 in Volume - IV which gives detailed output for the gross capacity of206.03 MCM.

7.1.1.1 Dead Storage Level (DSL)

One of the most important issues in the planning of storage reservoirsis the loss in the storage capacity due to silting. Hence, it is necessary at theplanning stage that a portion of the capacity of the reservoir is reserved foroccupation by silt deposition. By providing extra storage volume in thereservoir for sediment accumulation, in addition to the live storage, it isensured that the live storage will function at full efficiency for an assignednumber of years. This volume of storage (in addition of live storage) isreferred to as the dead storage and is equivalent to the volume of sedimentexpected to be deposited in the reservoir during the designed life of thestructure.

The sediment entering into a storage reservoir gets depositedprogressively with the passage of time and thereby reduces the dead as wellas live storage capacity of the reservoir. This causes the bed level near thedam to rise and the raised bed level is termed as “New Zero Elevation”. It istherefore necessary to assess the revised areas and capacities at variousreservoir elevations that would be available in future and could be used insimulation studies to test the reservoir performance and also the New ZeroElevation. As per IS: 12182 (1987) – “Guidelines for Determination ofEffects of Sedimentation in Planning and Performance of Reservoirs”. Thelive storage is to be so planned that the benefits do not reduce for a period of50 years (full service time) for irrigation or 25 years for hydropowerprojects connected to a grid on account of sedimentation. Also thesedimentation in the reservoir should not cause operational problems(sedimentation beyond the outlet) for 100 years for irrigation projects and

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70 years for hydropower projects in a grid. As Par-Tapi-Narmada LinkCanal project is being planned mainly for irrigation purpose, the reservoirsunder the link project are proposed to be planned in such a way that fullbenefits are available for 50 years and reservoirs will function normally forabout 100 years. Accordingly, sedimentation studies have been carried outfor 50 years (for reservoir simulation) and 100 years (for planning outlet).

The dead storage capacity of the Jheri reservoir has been fixed on thebasis of the guidelines given in “Fixing the capacities of reservoirs –Methods, Part 2 Dead storage, IS 5477 (Part 2): 1994”.

The new zero elevation of the Jheri reservoir has been worked out as185.00 m and 198.50 m after 50 years and 100 years respectively on thebasis of sedimentation studies. The corresponding capacities at these levelsas per the original Area - Capacity table come to 34 ha m and 868 ha mrespectively. However, Dead Storage Level of the reservoir has beenproposed as 199.00 m (corresponding original capacity of 923 ha m). Thedetails of sedimentation studies are furnished in Appendix 5.2 in Volume –IV.

7.1.1.2 Low Water Level /Minimum Draw-Down Level (MDDL)

The Minimum Draw Down Level (MDDL) of Jheri reservoir can befixed anywhere above 198.50 m which is the new zero elevation after 100years of operation of the reservoir, based on sedimentation studies carriedout by Hydrological Studies Organisation, CWC, New Delhi. Consideringthe delivery head requirement at Jheri reservoir for diversion of waters intoPaikhed reservoir through the 12.7 km long tunnel, the MDDL of Jherireservoir is kept at 204.00 m.

7.1.1.3 Full Reservoir Level (FRL)

Integrated simulation studies carried out for Jheri, Paikhed,Chasmandva, Chikkar, Dabdar and Kelwan reservoirs indicate that theproposed Jheri reservoir with Full Reservoir Level at 246.00 m will meetvarious planned demands at 100% success rate. Therefore, the FullReservoir Level of Jheri dam has been kept at 246.00 m.

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7.1.1.4 Maximum Water Level (MWL)

Maximum water level of Jheri reservoir has been kept as 247.00 mand the gates of spillway have been designed to pass design flood of 6539Cumecs. Various levels fixed at Jheri Reservoir are given in Table - 7.2.

Table -7.2Levels Fixed as per Simulation Study

Jheri Reservoir Elevation(m)MWL 247.00 mFRL 246.00 mMDDL 204.00 m

Jheri – Paikhed TunnelInvert level at entry 199.50 mCrown level at entry 202.50 mInvert level at exit 185.00 m

Crown level at exit 188.00 m

7.1.1.5 Maximum Backwater Level at Full Reservoir Level and Maximum Water Level and its Effect, Points to WhichBackwater Effect is Felt, Maximum Distance of Such Pointsfrom the Axis of the Structure

The Full Reservoir Level (FRL) and Maximum Water Level (MWL)of the Jheri dam have been fixed at 246.00 m and 247.00 m respectively.The maximum back water level at MWL is 247.00 m and the effect extendsup to a distance of about 14.60 km from the axis of the dam (at theperiphery of the reservoir) within which no structure of significantimportance has been identified.

7.1.1.6 Saddles along the Reservoir Rim

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The entire rim of proposed Jheri reservoir is covered with thecontours of value higher than the MWL as such no saddle is proposed alongthe rim of Jheri reservoir.

7.1.1.7 Fetch

The fetch of the reservoir was determined to fix the free board and thetop of the dam. The fetch computations were done as per the IndianStandards IS: 10635(Latest), “Guidelines for Free board requirements inEmbankment Dams”.

7.1.1.8 Direction of Wind - Velocity of Wind - Wave Height - FreeBoard-Top of Dam

The direction of wind in Jheri reservoir area is mostly from east to

west. The Nasik IMD station is located near to the Jheri dam site. Themaximum wind velocity of 13.2 km/hr is experienced in the month of Juneand the minimum wind velocity of 4.5 km/hr is experienced in the month ofDecember. The average velocity of wind is 8.4 km/hr. However, a normalwind velocity of 44 m/sec has been considered. The following factors aretaken into consideration while computing the free board requirement:

(a) Wave characteristics i.e. wave height and wave length; (b)Upstream slope of the dam and roughness of the pitching;(c) Height of wind setup above the still water level.

The details of free board requirement for all the six dams arefurnished in para 6.1.5 of Chapter – 6: Design Aspects. The top of the rock-fill portion of the Jheri dam has been fixed at 253.00 m.

7.1.2 Sedimentation Data and Studies

As a part of Hydrological Studies of Par-Tapi-Narmada Link Project,the Sedimentation Studies of the reservoirs proposed under the Link Projecthave been carried out by Hydrological Studies Organisation, CWC, NewDelhi. The details of sedimentation studies are furnished in Appendix 5.2 inVolume – IV and the gist of the studies is presented below.

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Previously, five reservoirs which are situated in the vicinity of Par-Tapi-Narmada Link Project were studied by Government of Gujarat todetermine the sedimentation rate in the region. Based on the hydrographicsurveys of Bhatsa, Dantiwada, Kanhar, Attaria-II and Machrewa-IIreservoirs in the vicinity, sedimentation rate was found in the range of 1.2 to2.0 acre-ft/sq mile/ year for South Gujarat area. Based on these studies, a siltrate of 1.5 acre-ft/ sq mile/ year (7.15 ham/ 100 sq.km/ year) was adopted inFeasibility Study of the Link Project. These figures included bed loadassumed as 15 % of the suspended load.

Presently, Sediment load is being measured in only three river basinsviz. Auranga (at Amba GandD site), Ambica (at Gadat GandD site) andPurna (at Mahuva GandD site) pertaining to Par-Tapi-Narmada LinkProject. The sedimentation rate assessed in these three river basins based onobserved daily discharges and sediment concentration are given in Table7.3.

Table -7.3Sediment Rate in Auranga, Ambica and Purna River Basins

S.No.

River GandD site Sediment Rate (mm/km2/year)

Suspended Load(SL)

Total Load(1.15*SL)

1 Auranga Amba 0.3831 0.44062 Ambica Gadat 0.2443 0.28103 Purna Mahuva 0.3693 0.4247

And also, based on the analysis of capacity survey data of 144reservoirs, rate of siltation in the existing dams were calculated and zonewise sedimentation rate was established in CWC’s document “Compendiumon Silting of Reservoirs in India”. In the document India is divided intoseven zones and silting rate for each zone is established based on thereservoirs located in the respective zones. Table 7.4 summarizes thepublished values of average and median siltation rate for the regions“Narmada and Tapi Basin” and “West Flowing Rivers beyond Tapi andSouth Indian Rivers”.

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Table -7.4Rate of Siltation as per

“Compendium on Silting of Reservoirs in India”Zone Region No. of

ReservoirsUnder Study

AverageRate ofSiltation(mm/year)

Median Valuesof Rate ofSiltation(mm/year)

6 Narmada and TapiBasin

3 0.729 0.75

7 West Flowing Riversbeyond Tapi andSouth Indian Rivers

19 3.533 1.79

But the sediment data is not available for Par and Nar rivers on whichJheri and Paikhed dams are proposed. Currently no sediment observationsare planned in the catchment area of Jheri dam. However, the Governmentof Gujarat had carried out sedimentation survey of existing Madhubanreservoir on Damanganga River, which lies in the vicinity of the LinkProject. Using this data the sedimentation rate at Jheri dam site has beenassessed.

7.1.2.1 Rate of Sedimentation with Basis

The sedimentation rates observed at GandD sites (Table-7.3) arerelatively lower as compared to sediment rate based on hydrographic surveyof five reservoirs in the region and much lower than the generalized siltationrate (Table-7.4) recommended for the region (west flowing rivers beyondTapi) in the “Compendium of Silting of Reservoirs in India”. Thehydrographic survey of existing reservoirs generally provide sound basis forthe assessment of sedimentation rate in the region. The hydrographic surveyof five reservoirs indicate sedimentation rate of 7.15 ham/100sq.km/year asabove. The hydrographic Survey of Madhuban reservoir in Damangangabasin, which lies towards south of Par-Tapi-Narmada link projects, gavesedimentation rate of 8.94 ham/100 sq.km/ year. Normal rainfall inDamanganga basin is higher than the normal rainfall in river basins of Par-Tapi-Narmada Link Project and therefore sedimentation rate of 7.15 ham/100 sq.km/year, as assessed based on hydrographic survey of reservoirs inthe region, appears in order. However the land use changes are likely to

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impact the sediment generation from the catchment in the future withincreasing human activities such as agriculture etc. Presently the catchmentof these river basins particularly the upper catchments are not significantlyaffected by the human activities. Impact of climate change is likely toincrease rainfall intensities and extreme meteorological events. In view ofabove factors, the observed sedimentation rate of 7.15 ham/100 sq.km/yearis enhanced by 25% and sedimentation rate of 8.94 say 9.0 ham/100sq.km/year has been adopted for analysis of all the reservoirs contemplatedunder Par-Tapi-Narmada Link Project.

7.1.2.2 Quantity of Sediment

Considering the inflow sedimentation rate of 9.0 ham/100 sq km/yearthe sediment volume at Jheri reservoir will be as under:

i) 50 years sediment volume 18.008 MCMii) 100 years sediment volume 35.938 MCM

7.1.2.3 Type and Shape of Reservoir

The Jheri reservoir is considered as hill type and the standardclassification is taken as Type III.

7.1.2.4 Sediment Studies – Jheri Reservoir

As per IS 5477 (Part – 2): 1994 (Fixing the capacities of reservoirs),either the “Empirical Area Reduction” method or the “Area Increment”method is recommended to be used for sedimentation study. In this report,the sedimentation study has been carried out using “Empirical AreaReduction” method.

7.1.2.5 Sediment Distribution

The sediment distribution is worked out for two periods, viz. 50 yearsand 100 years by Empirical Area Reduction method. For this purpose, the

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FRL 246.00 m is adopted and bed level of the reservoir is considered as 180m. The original Elevation-Area-Capacity table for Jheri reservoir is given inTable-7.5.

Table-7.5 Original Elevation-Area-Capacity Table for Jheri Reservoir

Elevation (m) Area ( ha) Capacity (MCM)246.00 836.42 206.03245.00 818.20 197.75242.00 758.51 174.11239.00 686.39 152.44236.00 590.39 133.31233.00 553.52 116.15230.00 487.80 98.76227.00 451.01 81.36224.00 414.09 68.39221.00 375.66 56.55218.00 320.41 46.12215.00 240.50 37.73212.00 215.10 30.90210.00 208.20 26.67208.00 190.33 22.69206.00 170.64 19.08204.00 152.65 15.85202.00 136.26 12.96200.00 120.00 10.40199.00 113.04 9.23198.00 105.56 8.14197.00 98.31 7.12196.00 91.34 6.17195.50 87.97 5.73195.00 84.60 5.30194.00 76.46 4.49193.00 68.72 3.76192.00 61.40 3.11191.00 54.49 2.54190.00 50.00 2.01189.00 41.49 1.56188.00 35.45 1.17187.00 30.90 0.84186.00 24.81 0.56

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Elevation (m) Area ( ha) Capacity (MCM)185.12 20.75 0.36185.00 20.20 0.34184.75 18.38 0.29184.50 16.56 0.25184.00 12.92 0.17183.00 7.27 0.07182.00 3.23 0.02181.00 0.81 0.00180.00 0.00 0.00

The total sediment during 50 and 100 years will get distributed up toand above various elevations as given in the Table-7.6 below:

Table-7.6Distribution of Total Sediment at Various Elevations of Jheri Dam

Reservoir Level Sediment Deposition in MCMAfter 50 Years After 100 Years

Up to 185 m 0.34 0.34Above 185 m 17.82 35.26Up to 199 m 5.89 9.24Above 199 m 12.27 26.36Up to 204 m 8.47 14.81Above 204 m 9.69 20.79

The new zero elevation will be as follows: After 50 years = 185.00 m After 100 years = 198.50 m

The Minimum Draw Down Level (MDDL) can be fixed anywhere above198.50 m which is the new zero elevation after 100 years of operation of thereservoir.

The plots of revised elevation-area-capacity curve for 50-Yearsedimentation and 100 year sedimentation are given in Figure – 7.1 and 7.2respectively:

Revised Elevation-Area-Capacity Curve

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for Jheri Dam after 50 yearsCapacity (MCM)

200 150 100 50 0

250 250

240 240

230 230

(m)

220 220

(m)

Ele

vati

on 210 210

Ele

vati

on

200 200

190 190

180 180

0 1 2 3 4 5 6 7 8

Area

Area (Sq Km)

Volume

Figure 7.1: Plot of revised elevation area capacity curve for Jheri dam after 50 years.

Revised Elevation-Area-Capacity Curve

for Jheri Dam after 100 yearsCapacity (MCM)

180 160 140 120 100 80 60 40 20 0250 250

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240 240

230 230

Ele

vati

on (

m) 220 220

Ele

vati

on (

m)

210 210

200 200

190 190

180 1800 2 4 6 8

Area (Sq Km)

Area Volume

Figure 7.2: Revised Elevation-Area-Capacity Curve for Jheri Dam after 100 years.

Original and revised (after 50 and 100 years) Elevation-Area-Capacity details for Jheri reservoir are given in Table-7.7 below:

Table-7.7 Original and Revised (after 50 and 100 years) Elevation – Area -

Capacity Table for Jheri ReservoirElevatio

nOrigina

lArea

OriginalCapacit

y

Revised AreaAfter

50Years

RevisedCapacity After

50 Years

RevisedAreaAfter100

Years

RevisedCapacity

After100

Years(m) (ha) (MCM) (ha) (MCM) (ha) (MCM)

246.00 836.42 206.03 836.42 187.87 836.42 170.43245.00 818.20 197.75 818.17 179.60 818.14 162.15242.00 758.51 174.11 757.85 155.96 757.10 138.53239.00 686.39 152.44 684.12 134.34 681.51 116.95236.00 590.39 133.31 585.49 115.31 579.87 98.04233.00 553.52 116.15 545.07 98.35 535.38 81.31230.00 487.80 98.76 475.01 81.27 460.33 64.60227.00 451.01 81.36 433.26 64.33 412.90 48.18224.00 414.09 68.39 390.97 51.97 364.45 36.52221.00 375.66 56.55 346.99 40.91 314.09 26.34218.00 320.41 46.12 286.23 31.42 247.03 17.94

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Elevation

Original

Area

OriginalCapacit

y

Revised AreaAfter

50Years


50 Years

RevisedAreaAfter100

Years

RevisedCapacity

After100


215.00 240.50 37.73 201.13 24.13 155.96 11.92212.00 215.10 30.90 171.09 18.55 120.61 7.77210.00 208.20 26.67 161.55 15.23 108.03 5.48208.00 190.33 22.69 141.48 12.20 85.43 3.55206.00 170.64 19.08 120.11 9.58 62.14 2.08204.00 152.65 15.85 101.04 7.37 41.83 1.04202.00 136.26 12.96 84.24 5.52 24.56 0.38200.00 120.00 10.40 68.32 4.00 9.02 0.04199.00 113.04 9.23 61.82 3.35 0.00 0.00198.00 105.56 8.14 55.02 2.77 0.00 0.00197.00 98.31 7.12 48.67 2.25 0.00 0.00196.00 91.34 6.17 42.82 1.79 0.00 0.00195.50 87.97 5.73 40.10 1.58 0.00 0.00195.00 84.60 5.30 37.43 1.39 0.00 0.00194.00 76.46 4.49 30.88 1.05 0.00 0.00193.00 68.72 3.76 24.98 0.77 0.00 0.00192.00 61.40 3.11 19.73 0.55 0.00 0.00191.00 54.49 2.54 15.15 0.37 0.00 0.00190.00 50.00 2.01 13.24 0.23 0.00 0.00189.00 41.49 1.56 7.56 0.13 0.00 0.00188.00 35.45 1.17 4.60 0.07 0.00 0.00187.00 30.90 0.84 3.37 0.03 0.00 0.00186.00 24.81 0.56 0.84 0.00 0.00 0.00185.12 20.75 0.36 0.09 0.00 0.00 0.00185.00 20.20 0.34 0.00 0.00 0.00 0.00184.00 12.92 0.17 0.00 0.00 0.00 0.00183.00 7.27 0.07 0.00 0.00 0.00 0.00182.00 3.23 0.02 0.00 0.00 0.00 0.00181.00 0.81 0.00 0.00 0.00 0.00 0.00180.00 0.00 0.00 0.00 0.00 0.00 0.00

7.1.3 Life of Reservoir in Years with Basis

All the outlets from the reservoir are fixed at an elevation abovethe New Zero Elevation estimated after considering 100 years of

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sedimentation. Therefore, the life of the Jheri reservoir has been consideredas 100 years.

7.1.4 Capacity 7.1.4.1 Capacities of Jheri Reservoir

SNo.

Capacity (MCM)Initial After 50

YearsAfter 100

Years1 Gross storage capacity 206.03 187.87 170.432 Live storage capacity 190.18 180.50 169.393 Storage capacity at MDDL 15.85 7.37 1.044 Dead storage capacity (at

DSL) 9.23 3.35 0.00

7.1.4.2 Storage

Simulation analysis considering the inflow and various waterdemands to be met from Jheri reservoir has been carried out. Based on thesimulation analysis the live storage has been provided so that the demand ofwater for various requirements could be met. The dead storage has beenprovided so that the functioning of the project would not be affected evenafter accumulation of silt over a period of 100 years. Various storage detailsof the proposed Jheri reservoir have been mentioned in the Para 7.1.4.1above.

The initial storage of each reservoir planned under the Link Project isassumed as 10% of live storage plus storage at MDDL for simulationanalysis. No storage capacity is reserved for downstream use under any ofthe proposed reservoirs. The monthly minimum storages reserved in Jherireservoir for meeting the water demands towards evaporation losses,environmental (10% of 75% dependable lean season flow) and domesticneeds to achieve intended success rates are given in Table-7.8 below:

Table-7.8Monthly Minimum Storages Reserved in Jheri Reservoir for Meeting

Evaporation Losses, Environmental and Domestic Needs

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Unit: MCM

Jun Jul Aug Sept Oct Nov Dec Jan Feb March Apr May2 2 2 2 2 12 10 10 7 6 4 2

The monthly inflow series and monthly diversion requirementsconsidered for simulation analysis of Jheri reservoir for fixing its livestorage are furnished in Appendix 5.5 in Volume – IV.

7.1.4.3 Water Tightness of the Reservoir

Preliminary Geotechnical Investigations were carried out at the damsite by GSI, Western Region, Jaipur at Feasibility Report stage of Par-Tapi-Narmada Link Project during 1993-94. As per these investigations thefoundation rocks at the dam site are massive and amygdular basalts whichare jointed and sheared, particularly at the flow contacts. Hence, specialattention shall be needed to delineate the flow contacts and their structuralconditions, necessitating selective treatment to improve their strength andimperviousness.

The Jheri reservoir area is thickly forested and restricted to the valleywith steep hills on both sides. Amygdular basalts which are jointed andsheared are encountered in the area. No major fault or shear zone was notedin the area. The reservoir appears to be water tight. The reports of GSI are atAppendix – 4.2 and 4.4 in Volume – III. Also the periphery of the proposedJheri reservoir is covered with the contours of value higher than the MWL.

7.1.4.4 Annual Losses

The simulation study carried out for Jheri reservoir for the periodfrom 1975 to 2006 indicates that the annual average evaporation loss fromJheri reservoir is 10.3 MCM with highest evaporation loss as 11.3 MCMduring the years 1994 and 2005 and the lowest evaporation loss as 7.9MCM during the year 1987. Maximum Monthly evaporation loss is in Maymonth and least Monthly evaporation loss is in July.

7.1.4.5 Flood Absorption

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No flood storage is earmarked for this project. However, fromreservoir routing it is seen that the maximum water level attained was247.00 m and the maximum outflow discharge was 6586 Cumec.

7.1.5 Effects on Sub Soil Water Table in the Adjoining AreasParticularly Downstream of the Dam

The sub-soil water table will improve due to the impoundment ofwater in the Jheri reservoir. In addition, the regulated flows from the Jheridam into Par River to meet environmental needs will increase the sub soilwater level in the adjoining areas even during lean season.

7.1.6 Reservoir Rim Stability

The entire Reservoir area lies in the Deccan volcanoes. The rock typeencountered is moderately to highly amygdular basalt, which is generallynon-porphyritic in nature with occasional thin bands of massive basaltoccurring in it. Occasional dykes of dolerite composition have beenobserved.

The reservoir area appears to be water tight with no perceptible shearor fault zone criss-crossing the area.

7.1.7 Area of Submergence 7.1.7.1 At Maximum Water Level

Area of submergence of Jheri reservoir at MWL is 905 ha.

7.1.7.2 At Full Reservoir Level

Area of submergence of Jheri reservoir at FRL is 836 ha.

7.1.7.3 Submergence Ratio - Submerged (Cultivated) Area/CCA

The Jheri reservoir is a part of net-work of 6 reservoirs proposedunder Par-Tapi-Narmada Link Project for diversion of surplus waters of Par,Auranga, Ambica and Purna rivers for en-route irrigation and to take-overpart command of Narmada Main Canal. The irrigation water requirement of

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the Link Project will be met in an integrated manner i.e. first attempt will beto meet the irrigation needs from the nearest reservoir (Kelwan) and if thereis any shortage of water at the reservoir, the water will be drawn from thesuccessive reservoirs up to the Jheri reservoir. It implies that the storagesavailable at all the six reservoirs will be utilized for meeting the irrigationdemand of the Link Project. As such, the submergence ratio should beworked considering the total submergence area (cultivated) under sixreservoirs and the total CCA of the Link Project. The total submergence area(cultivated) under the six reservoirs is 2364 ha and the total CCA of theLink project is 232175 ha. Therefore, the Submergence Ratio works out to0.0102.

7.1.8 Land Acquisition-Property Submerged-Rehabilitation 7.1.8.1 Land Acquisition

The land to be acquired is about 836 ha (forest land: 408 ha,cultivable land: 256 ha and other lands including river portion: 172 ha) thatis coming under submergence of Jheri reservoir.

7.1.8.2 Details of Property Submerged

Due to creation of Jheri reservoir 6 villages will be partially affected. Allthese villages come under Peint and Surgana talukas of Nasik district ofMaharashtra. Total 98 households of these villages are likely to be affected.

(i) Details of Dislocation of Communication (Railways), Road(s), Rightof Way, Telegraph Lines etc.) as a Result of the Project

No railway line is coming under the submergence area of Jheri reservoir.Major road connecting Peint to Surgana is passing through the Submergencearea of Jheri dam and approximately 1 km length is under the submergence.No telegraph/ telephone line needs to be dislocated as a result of the project.

(ii) Details of Valuable Mineral Deposits / Mines

The Engineering Geology Division of GSI, Jaipur vide Letter No.171/G-1/EG/WR/GSI08-09 dated 9th April, 2009 (Annexure – 4.3 in

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Volume -II) informed that no significant minerals have been reported fromthe Jheri reservoir area, except construction material and a few minorminerals like zeolites.

(iii) Historic/Archaeological Monuments

As already mentioned under “Chapter – 4: Surveys andInvestigations-Para 4.2.1 Archaeological Survey”, no antiquarianarchaeological remains have been noticed and none of the centrallyprotected monuments are located in the area likely to be submerged due toconstruction of Jheri dam.

7.1.8.3 Rehabilitation of Project Affected People

The objective of development is poverty alleviation, social justice anda better quality of life for people. Some development situations howeverentail displacement of populations and adverse impacts including disruptionof social and kinship networks and livelihoods and other economic orcultural loss.

Lack of development, however, can also impact on the environmentand lead to distress migration. Involuntary displacement by dams or otherwater resource projects must therefore be sought to be converted into adevelopment opportunity that leaves those affected better off throughenlightened processes of resettlement and rehabilitation. The Social andOccupational profile of the people of the project area is described in theChapter -12 “Socio- economic Studies and RandR Plan”.

Due to creation of Jheri reservoir 98 households/families are likely tobe affected. These Project Affected People (PAPs) are to be compensated fortheir loss of land, home etc, for which an RandR package has been evolved.The process of RandR has three distinct components: relocation of PAPs toa new location where necessary; resettlement in that location and therestoration of livelihood; and rehabilitation so that every individual couldregain and/or improve his/her life and socio-economic status within areasonable time after displacement.

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The RandR package for PAPs has been devised considering theprovisions of “National Policy on Rehabilitation and Resettlement -2007”formulated by Ministry of Rural Development, Government of India, asbasic minimum criteria. Due weightage has also been given to variousprovisions of the Resettlement and Rehabilitation (RandR) Plan adopted forSardar Sarovar Project by the States of Gujarat, Madhya Pradesh andMaharashtra.

Resettlement and Rehabilitation (RandR) Plan adopted for SardarSarovar Project by the States of Gujarat, Madhya Pradesh and Maharashtrahas been reviewed and compared with NPRR, 2007 and the best norms ofeach policy have been adopted. People’s perception on the resettlementaspects and facilities they expect in the area where they are supposed to beresettled after displacement and preferences of affected populationregarding compensation package, whether it should be in cash or kind havealso been considered while formulating the Resettlement and Rehabilitationpackage for the people likely to be affected due to the submergence of Jheri,Paikhed, Chasmandva, Chikkar, Dabdar and Kelwan reservoirs. The detailsof R and R package are described in the Chapter – 12 (Socio- economicstudies and RandR plan).

7.1.9 Recreation Facilities

Following are the recreational facilities which are proposed to bedeveloped.

Development of parks/gardens in d/s of dam.

Development of Children parks in the township.

Development of Tourist spot with boating facilities

Development of Guest house, inspection bungalow and

dormitory accommodation.

These facilities will ensure tourism development in the area.

7.1.10 Pisciculture

The submergence area of Jheri reservoir is 836 ha and there is lot ofscope for developing fisheries. Based on literature review, the present

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average fish production rate in Indian reservoirs is given in Table – 7. 9below:

Table – 7.9Average Fish Production Rates in ReservoirsReservoir Type Yield (kg/ ha)Small 49.90Medium 12.30Large 11.43

Fish Seed Committee of the Government of India (1966) termed allwater bodies of more than 200 ha in area as reservoirs. David et al. (1974)while classifying the water bodies of Karnataka State, consideredimpoundments above 500 ha as reservoirs and named the smaller ones asirrigation tanks.

Reservoirs are classified generally as small (<1000 ha), medium(1000 to 5000 ha) and large (> 5000 ha), especially in the records of theGovernment of India (Sarma, 1990, Srivastava et al., 1985), which has beenfollowed in the present study.

Considering the water spread area of Jheri reservoir and the fishproduction rate indicated above, expected fish production in Jheri reservoirwill be about 42 tonnes per year which will increase the revenue from theproject.

7.1.11 Need and Recommendation for Soil Conservation Measuresin the Catchment

The chances of soil erosion, if any can be prevented/minimized byadopting following measures:

Step drain

Angle iron barbed wire fencing

Stone masonry

Check dams

Contour bunding

Development of nurseries

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Plantation/ afforestation

Pasture development

Social forestry

Appropriate financial provisions have been provided for soilconservation measures in the catchment area.

7.2. Paikhed Reservoir7.2.1. Fixation of Storage and Reservoir Levels - Approach–Criteria

The water availability studies at Jheri, Paikhed, Chasmandva,Chikkar, Dabdar and Kelwan dam sites have been carried out by theHydrological Studies Organisation, CWC, New Delhi as a part of“Hydrological Studies of Par-Tapi-Narmada Link Project”. The Gross andNet Annual Yields at Paikhed dam site as per these studies are as given inTable: 7.10 below.

Table: 7.10 Gross and Net Annual Yields at Paikhed Dam Site

S.No.



The net water availability at Paikhed dam site has been worked outafter subtracting all the consumptive upstream utilizations planned byStates. Regeneration from major and medium irrigation projects has beentaken as 10 percent while the same has been ignored in case of minorirrigation projects. The regeneration from domestic and industrial uses hasbeen considered as 80 percent of water diverted for the purpose. The netyield series generated at Paikhed dam site for the period from 1975-76 to2006-07 is at Annexure: 5.14 in Volume – II.

The reservoir simulation study has been carried out for estimating thelive storage capacity of the reservoir that would provide the required yield atspecified reliability. The discharge data is available for a period of 39 years

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from 1966 to 2004 at Nanivahiyal G and D site maintained by Governmentof Gujarat on Par River, which is located d/s of Paikhed dam site. Rainfall –Runoff model has been developed using discharge data available atNanivahiyal G and D site and rainfall for the concurrent period. The flowdata of inconsistent years have been discarded while developing Rainfall-Runoff model. Using this Rainfall – Runoff model the gross yield series forthe period from 1975-76 to 2006-07 at Paikhed dam site has beendeveloped. The net yield series at the dam site has been generated bysubtracting the net upstream consumptive use from the gross yield seriesand used for simulation analysis.

The simulation analysis has been done using Simulation Programdeveloped using c++. This programme also takes into account the differentreleases from Paikhed reservoir: i) for local domestic and industrial waterdemand, ii) environmental and ecological requirements downstream ofproposed dam site and iii) downstream releases for further transfer to Par-Tapi-Narmada Link Canal. The result of this analysis is at Appendix 5.5 inVolume - IV which gives detailed output for the gross capacity of 229.53MCM.


The dead storage capacity of the Paikhed reservoir has been fixed onthe basis of the guidelines given in “Fixing the capacities of reservoirs –Methods, Part 2 Dead storage, IS 5477 (Part 2): 1994”.

The new zero elevation of the Paikhed reservoir has been worked out

as 164.34 m and 171.88 m after 50 years and 100 years respectively on thebasis of sedimentation studies. The corresponding capacities at these levelsas per the original Area - Capacity table come to 1.59 ha m and 89.36 ha mrespectively. However, Dead Storage Level of the reservoir has beenproposed as 172.00 m (corresponding original capacity of 92 ha m) andsluices are proposed to be provided above this level. The details ofsedimentation studies are furnished in Appendix 5.2 in Volume – IV.


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The Minimum Draw Down Level (MDDL) of Paikhed reservoir canbe fixed anywhere above 171.88 m which is the new zero elevation after100 years of operation of the reservoir, based on sedimentation studiescarried out by Hydrological Studies Organisation, CWC, New Delhi.Keeping in view the live storage requirement for meeting the Link Canaldemands and power generation, the MDDL of Paikhed reservoir is kept at190.00 m.


Integrated simulation studies carried out for Jheri, Paikhed,Chasmandva, Chikkar, Dabdar and Kelwan reservoirs indicate that theproposed Paikhed reservoir with Full Reservoir Level at 248.00 m will meetvarious planned demands at 100% success rate. Therefore, the FullReservoir Level of Paikhed dam has been kept at 248.00 m.


Maximum water level of Paikhed reservoir has been kept as249.00 m and the gates of spillway have been designed to pass design floodof 5307 Cumecs.

The Maximum Water Level at Paikhed dam has been fixed as 249.00m. Various levels fixed at Paikhed Reservoir are given in Table - 7.11.


Paikhed Reservoir Elevation(m)MWL 249.00FRL 248.00MDDL 190.00

7.2.1.5 Maximum Backwater Level at Full Reservoir Level andMaximum Water Level and its Effect, Points to WhichBackwater Effect is Felt, Maximum Distance of Such Pointsfrom the Axis of the Structure

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The Full Reservoir Level (FRL) and Maximum Water Level (MWL)of the Paikhed dam have been fixed at 248.00 m and 249.00 m respectively.The maximum back water level at MWL is 249.00 m and the effect extendsup to a distance of about 17.40 km from the axis of the dam (at theperiphery of the reservoir) within which no structure of significantimportance has been identified.


The entire rim of proposed Paikhed reservoir is covered with thecontours of value higher than the MWL as such no saddle is proposed alongthe rim of Paikhed reservoir.

7.2.1.7 Fetch



The direction of wind in Paikhed reservoir area is mostly from east to

west. The Nasik IMD station is located near to the Paikhed dam site. Themaximum wind velocity of 13.2 km/hr is experienced in the month of Juneand the minimum wind velocity of 4.5 km/hr is experienced in the month ofDecember. The average velocity of wind is 8.4 km/hr. However, a normalwind velocity of 44 m/sec has been considered. The following factors aretaken into consideration while computing the free board requirement:

(a) Wave characteristics i.e. wave height and wave length; (b) Upstream slope of the dam and roughness of the pitching;(c) Height of wind setup above the still water level.

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The details of free board requirement for all the six dams arefurnished in para 6.1.5 of Chapter – 6: Design Aspects. The top of the rock-fill portion of the Paikhed dam has been fixed at 255 m.


Sediment data is not available for Nar River on which Paikhed dam isproposed. Currently no sediment observations are planned in the catchmentarea of Paikhed dam. However, the Government of Gujarat had carried outsedimentation survey of existing Madhuban reservoir on DamangangaRiver, which lies in the vicinity of the Link Project. Using this data thesedimentation rate at Paikhed dam site has been assessed.


A sedimentation rate of 9.0 ham/100 sq.km/year has been adopted foranalysis of Paikhed reservoir. The basis for adopting the value has alreadybeen explained under Para 7.1.2.1 above.


Considering the inflow sedimentation rate of 9.0 ham/100 km2/yearthe sediment volume at Paikhed reservoir will be as under.



The Paikhed reservoir is considered as Flood plain-foot hill type and the standard classification is taken as Type II.

7.2.2.4 Sediment Studies – Paikhed Reservoir

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The sedimentation study has been carried out using “Empirical AreaReduction” method.


The sediment distribution is worked out for two periods, viz. 50 yearsand 100 years by Empirical Area Reduction method. For this purpose, theFRL 248.00 m is adopted and bed level of the reservoir is considered as163.14 m. The original Elevation-Area-Capacity table for Paikhed reservoiris given in Table-7.12:

Table-7.12 Original Elevation-Area-Capacity Table for Paikhed Reservoir

Elevation (m)

Area (ha)

Capacity(MCM)

248.00 993.57 229.53

245.00 890.19 201.28

242.00 781.20 176.23

239.00 684.19 154.27

236.00 602.75 134.97

233.00 528.40 118.02

230.00 459.89 104.06

227.00 414.53 90.10

224.00 368.02 78.36

221.00 317.73 68.09

218.00 281.97 59.10

215.00 253.51 51.07

212.00 227.80 43.85

209.00 203.43 37.39

206.00 180.36 31.63

203.00 156.08 26.59

200.00 132.30 22.27

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Elevation (m)

Area (ha)

Capacity(MCM)

198.00 122.90 19.72

196.00 115.06 17.34

194.00 105.63 15.13

192.00 97.75 13.10

190.00 90.17 11.22

188.00 83.04 9.49

186.00 76.19 7.90 184.00 68.74 6.45

182.00 60.81 5.16

180.00 53.38 4.01

179.00 49.74 3.50

178.00 46.24 3.02

177.00 42.86 2.57

176.00 39.61 2.16

175.00 36.49 1.78

174.00 31.15 1.44

173.00 26.22 1.16

172.00 21.72 0.92

171.50 19.69 0.81

171.00 17.65 0.72

170.50 15.82 0.64

170.00 13.99 0.56

169.00 12.40 0.43

168.00 10.91 0.31

167.00 9.51 0.21

166.00 8.21 0.12

165.00 7.00 0.05

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Elevation (m)

Area (ha)

Capacity(MCM)

164.51 4.43 0.02

164.50 4.38 0.02

164.00 1.75 0.01

163.14 0.00 0.00


Table-7.13Distribution of Total Sediment at Various Elevations of Paikhed DamReservoir Level Sediment Deposition in MCM

After 50 Years After 100 YearsUp to 164.34 m 0.02 0.02Above 164.34 m 13.64 27.08Up to 172.00 m 0.60 0.92Above 172.00 m 13.06 26.18Up to 192.00 m 3.64 7.00Above 192.00 m 10.02 20.10

The new zero elevation will be as follows:

After 50 years = 164.34 m After 100 years = 171.88 m

The Minimum Draw Down Level (MDDL) can be fixed anywhereabove 171.88 m which is the new zero elevation after 100 years of operationof the reservoir. The plots of revised elevation-area-capacity curve for 50-Year sedimentation and 100 year sedimentation are given in Figure – 7.3and 7.4 respectively.

Revised Elevation-Area-Capacity Curvefor Paikhed Dam after 50 years

Capacity (MCM)200 150 100 50 0

243 243

233 233

223 223

(m)

213 213 (m)

460

Ele

vati

on 203 203

Ele

vati

on

193 193

183 183

173 173

163 1630 200 400 600 800

AreaArea (Ha) Volume

Figure 7.3: Plot of revised elevation area capacity curve for Paikhed dam after 50 years

Revised Elevation-Area-Capacity Curvefor Paikhed Dam after 100 years

Capacity (MCM)200 150 100 50 0

243 243

233 233

223 223

(m)

213 213 (m)

Ele

vati

on 203 203

Ele

vati

on

193 193

183 183

173 173

163 1630 100 200 300 400 500 600 700 800 900

Area (Ha)AreaVolume

Figure 7.4: Revised Elevation-Area-Capacity Curve for Paikhed Dam after 100 years

Original and revised (after 50 and 100 years) Elevation-Area-Capacity details for Paikhed reservoir are given in Table-7.14 below:


Capacity Table for Paikhed Reservoir

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Elevation OriginalArea

OriginalCapacity

RevisedArea

After 50Years

RevisedCapacityAfter 50

Years

RevisedArea

After 100Years



248.00 993.57 229.53 993.57 215.87 993.57 202.43245.00 890.19 201.28 880.13 187.73 870.02 174.39242.00 781.20 176.23 768.11 163.02 754.97 150.03239.00 684.19 154.27 669.07 141.48 653.89 128.92236.00 602.75 134.97 586.13 122.66 569.43 110.58233.00 528.40 118.02 510.61 106.22 492.75 94.66230.00 459.89 104.06 441.20 91.96 422.42 80.94227.00 414.53 90.10 395.13 79.42 375.65 68.98224.00 368.02 78.36 348.08 68.28 328.06 58.43221.00 317.73 68.09 297.40 58.61 276.99 49.36218.00 281.97 59.10 261.38 50.23 240.70 41.60215.00 253.51 51.07 232.77 42.82 211.95 34.82212.00 227.80 43.85 207.03 36.23 186.17 28.85209.00 203.43 37.39 182.73 30.38 161.94 23.63

206.00 180.36 31.63 159.83 25.25 139.21 19.12 203.00 156.08 26.59 135.81 20.82 115.46 15.30 200.00 132.30 22.27 112.40 17.10 92.41 12.19 198.00 122.90 19.72 103.29 14.94 83.61 10.43 196.00 115.06 17.34 95.80 12.95 76.45 8.83 194.00 105.63 15.13 86.75 11.13 67.80 7.38 192.00 97.75 13.10 79.31 9.47 60.79 6.10 190.00 90.17 11.22 72.21 7.95 54.18 4.95 188.00 83.04 9.49 65.62 6.58 48.12 3.93 186.00 76.19 7.90 59.35 5.33 42.45 3.02 184.00 68.74 6.45 52.55 4.21 36.29 2.24

182.00 60.81 5.16 45.33 3.23 29.79 1.58180.00 53.38 4.01 38.68 2.39 23.92 1.04179.00 49.74 3.50 35.46 2.02 21.12 0.81178.00 46.24 3.02 32.40 1.68 18.50 0.62177.00 42.86 2.57 29.48 1.37 16.04 0.44176.00 39.61 2.16 26.71 1.09 13.76 0.29175.00 36.49 1.78 24.11 0.84 11.67 0.17174.00 31.15 1.44 19.31 0.62 7.41 0.07173.00 26.22 1.16 14.95 0.45 3.63 0.02172.00 21.72 0.92 11.06 0.32 0.00 0.00171.50 19.69 0.81 9.34 0.27 0.00 0.00171.00 17.65 0.72 7.64 0.23 0.00 0.00

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OriginalCapacity

RevisedArea

After 50Years


Years

RevisedArea

After 100Years



170.50 15.82 0.64 6.15 0.19 0.00 0.00170.00 13.99 0.56 4.68 0.16 0.00 0.00169.00 12.40 0.43 3.84 0.12 0.00 0.00168.00 10.91 0.31 3.18 0.09 0.00 0.00167.00 9.51 0.21 2.69 0.06 0.00 0.00166.00 8.21 0.12 2.44 0.03 0.00 0.00165.00 7.00 0.05 2.46 0.01 0.00 0.00164.51 4.43 0.02 0.60 0.00 0.00 0.00164.50 4.38 0.02 0.57 0.00 0.00 0.00164.00 1.75 0.01 0.11 0.00 0.00 0.00163.14 0.00 0.00 0.00 0.00 0.00 0.00


All the outlets from the reservoir are fixed at an elevation abovethe New Zero Elevation estimated after considering 100 years ofsedimentation. Therefore, the life of the Paikhed reservoir has beenconsidered as 100 years.

7.2.4 Capacity7.2.4.1 Capacities of Paikhed ReservoirSNo.


YearsAfter 100


DSL) 0.92 0.32 0.00

7.2.4.2 Storage

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Simulation analysis considering the inflow and various waterdemands to be met from Paikhed reservoir has been carried out. Based onthe simulation analysis the live storage has been provided so that thedemand of water for various requirements could be met. The dead storagehas been provided so that the functioning of the project would not beaffected even after accumulation of silt over a period of 100 years. Variousstorage details of the proposed Paikhed reservoir have been mentioned inthe Para 7.2.4.1 above.

The monthly minimum storages reserved in Paikhed reservoir formeeting the water demands towards evaporation losses, environmental anddomestic needs to achieve intended success rates are given in Table-7.15below:

Table-7.15Monthly Minimum Storages Reserved in Paikhed Reservoir for

Meeting Evaporation Losses, Environmental and Domestic Needs

Unit:MCM

J J Aug

Sept

ONov

DJ F March

April

May

2 2 2 3 1 10

8 8 6 6 4 3

The monthly inflow series and monthly diversion requirements consideredfor simulation analysis of Paikhed reservoir for fixing its live storage arefurnished in Appendix 5.5 in Volume – IV.


DPR stage Geotechnical investigations were carried out at Paikheddam site by Engineering Geology Division, Western Region, GSI, Jaipurduring the field season 2009-10. A total of 12 number of exploratory boreholes have been drilled in the different sections of the proposed dam site atPaikhed. The bore hole core logging aggregating a total length of 622.95 m

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has been carried out. Basalts of the Deccan trap forms the foundation rock atthe project area. The rocks have horizontal to sub horizontal dips. Thewater percolation test results of these bore holes indicate that the strata ingeneral have low permeability but higher values of equivalent permeabilityup to 15 lugeons has been worked out in one section of bore hole number 9.In the left abutment and NOF from R.D. 0 to R.D.180, no bore hole hasbeen drilled. Additional bore holes should be drilled in this section to knowthe suitable foundation grade. Since the rocks in the area have a horizontalto sub horizontal disposition, there may be the need of consolidationgrouting / anchoring, which may be decided after the excavation has beendone.

The reservoir appears to be water tight. The report of GSI is atAppendix – 4.5 in Volume – III.


The simulation study carried out for Paikhed reservoir for the periodfrom 1975 to 2006 indicates that the annual average evaporation loss fromPaikhed reservoir is 6.8 MCM with highest evaporation loss as 8.5 MCMduring the year 1976 and the lowest evaporation loss as 4.2 MCM duringthe year 1995. Maximum Monthly evaporation loss is in December monthand least Monthly evaporation loss is in June.




The sub-soil water table will improve due to the impoundment ofwater in the Paikhed reservoir. In addition, the regulated flows from thePaikhed dam into Nar River to meet environmental needs will increase thesub soil water level in the adjoining areas even during lean season.

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The detailed geological mapping to analyze the problems of reservoirstability and reservoir competency with respect to seepage/leakage of theproposed Paikhed reservoir could not be carried out due to public hindranceeither during FR stage or DPR stage. However, in order to evaluate the sub-surface rock/over burden conditions of the Paikhed dam site has beenexplored by 12 numbers of NX size bore holes. The bore hole cores havebeen logged and their data was analysed to find out foundation grade levelsand water tightness of bed rock as well as to ascertain the soil structure andits permeability characteristics. However, no reservoir rim stabilityproblems are anticipated in view of the type of rock formationpresent at the periphery of the submergence area.


Area of submergence of Paikhed reservoir at MWL is 1089 ha.


Area of submergence of Paikhed reservoir at FRL is 994 ha. 7.2.7.3 Submergence Ratio - Submerged (Cultivated) Area/CCA

The Paikhed reservoir is a part of net-work of 6 reservoirs proposedunder Par-Tapi-Narmada Link Project for diversion of surplus waters of Par,Auranga, Ambica and Purna rivers for en-route irrigation and to take-overpart command of Narmada Main Canal. The total submergence area(cultivated) under the six reservoirs is 2364 ha and the total CCA of theLink project is 232175 ha. Therefore, the Submergence Ratio works out to0.0102.


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The land to be acquired is about 994 ha (forest land: 317 ha,cultivable land: 589 ha and other lands including river portion: 88 ha) that iscoming under submergence of Paikhed reservoir.


Due to creation of Paikhed reservoir 11 villages will be affected. Thesevillages come under Dharampur taluka of Valsad district of Gujarat andSurgana taluka of Nasik district of Maharashtra. Total 331 households ofthese villages are likely to be affected.

(ii)Details of Dislocation of Communication (Railways), Road(s), Rightof Way, Telegraph Lines etc.) as a result of the Project

No railway line is coming under the submergence area of Paikhedreservoir. Major road connecting Sidumber-Tutarkhed is passing through theSubmergence area of Paikhed dam. No telegraph/ telephone line needs to bedislocated as a result of the project.

(iii) Details of Valuable Mineral Deposits / Mines

The Engineering Geology Division of GSI, Jaipur vide Letter No. 171/G-1/EG/WR/GSI08-09 dated 9th April, 2009 (Annexure – 4.3-- in Volume -II)informed that no significant minerals have been reported from the Paikhedreservoir area, except construction material and a few minor minerals likezeolites.


As already mentioned under “Chapter – 4: Surveys andInvestigations-Para 4.2.1 Archaeological Survey”, no antiquarianarchaeological remains have been noticed and none of the centrallyprotected monuments are located in the area likely to be submerged due toconstruction of Paikhed dam.

467


The rehabilitation plan has already been detailed under Para 7.1.8.3 above.









7.2.10 Pisciculture

The submergence area of Paikhed reservoir is 994 ha and there islot of scope for developing fisheries.

Considering the water spread area of Paikhed reservoir and the fishproduction rate indicated above, expected fish production in Paikhedreservoir will be about 50 tonnes per year which will increase the revenuefrom the project.

7.2.11 Need and Recommendation for Soil Conservation Measurein the Catchment


Step drain


468

Stone masonry

Check dams

Contour bunding



Pasture development

Social forestry


7.3. Chasmandva Reservoir7.3.1. Fixation of Storage and Reservoir Levels - Approach–Criteria

The water availability studies at Jheri, Paikhed, Chasmandva,Chikkar, Dabdar and Kelwan dam sites have been carried out by theHydrological Studies Organisation, CWC, New Delhi as a part of“Hydrological Studies of Par-Tapi-Narmada Link Project”. The Gross andNet Annual Yields at Chasmandva dam site as per these studies are as givenin Table: 7.16 below:

Table: 7.16 Gross and Net Annual Yields at Chasmandva Dam Site

S.No.



The net water availability at Chasmandva dam site has been workedout after subtracting all the consumptive upstream utilizations planned byStates. Regeneration from major and medium irrigation projects has beentaken as 10 percent while the same has been ignored in case of minorirrigation projects. The regeneration from domestic and industrial uses hasbeen considered as 80 percent of water diverted for the purpose. The netyield series generated at Chasmandva dam site for the period from 1975-76to 2006-07 is at Annexure: 5.15 in Volume - II.

469

The reservoir simulation study has been carried out for estimating thelive storage capacity of the reservoir that would provide the required yield atspecified reliability. The discharge data is available for a period of 43 yearsfrom 1962 to 2004 at Amba G and D site maintained by Government ofGujarat on Tan River, which is located d/s of Chasmandva dam site. Rainfall– Runoff model has been developed using discharge data available at AmbaG and D site and rainfall for the concurrent period. The flow data ofinconsistent years have been discarded while developing Rainfall-Runoffmodel. Using this Rainfall – Runoff model the gross yield series for theperiod from 1975-76 to 2006-07 at Chasmandva dam site has beendeveloped. The net yield series at the dam site has been generated bysubtracting the net upstream consumptive use from the gross yield seriesand used for simulation analysis.

The simulation analysis has been done using Simulation Programdeveloped using c++. This programme also takes into account the differentreleases from Chasmandva reservoir: i) for local domestic and industrialwater demand, ii) environmental and ecological requirements downstreamof proposed dam site, and iii) downstream releases for further transfer toPar-Tapi-Narmada Link Canal. The result of this analysis is at Appendix 5.5in Volume - IV which gives detailed output for the gross capacity of 83.63MCM.


The dead storage capacity of the Chasmandva reservoir has beenfixed on the basis of the guidelines given in “Fixing the capacities ofreservoirs – Methods, Part 2 Dead storage, IS 5477 (Part 2): 1994”.

The new zero elevation of the Chasmandva reservoir has been worked outas 171.75 m and 176.00 m after 50 years and 100 years respectively on thebasis of sedimentation studies. The corresponding capacities at these levelsas per the original Area - Capacity table come to 2.73 ha m and 36.54 ha mrespectively. However, Dead Storage Level of the reservoir has beenproposed as 176.00 m (corresponding original capacity of 36.54 ha m) andsluices are proposed to be provided above this level. The details ofsedimentation studies are furnished in Appendix 5.2 in Volume – IV.

470


The Minimum Draw Down Level (MDDL) of Chasmandva reservoircan be fixed anywhere above 176 m which is the new zero elevation after100 years of operation of the reservoir, based on sedimentation studiescarried out by Hydrological Studies Organisation, CWC, New Delhi.Keeping in view the live storage requirement for meeting the Link Canaldemands and power generation, the MDDL of Chasmandva reservoir is keptat 190.00 m.


Integrated simulation studies carried out for Jheri, Paikhed,Chasmandva, Chikkar, Dabdar and Kelwan reservoirs indicate that theproposed Chasmandva reservoir with Full Reservoir Level at 214.00 m willmeet various planned demands at 100% success rate. Therefore, the FullReservoir Level of Chasmandva dam has been kept at 214.00 m.


Maximum Water Level of Chasmandva reservoir has been kept as215.0 m and the gates of spillway have been designed to pass design floodof 2578 Cumec.

The Maximum Water Level at Chasmandva dam has been fixed as215.0 m. Various levels fixed at Chasmandva Reservoir are given in Table -7.17.


Chasmandva Reservoir Elevation(m)MWL 215.00FRL 214.00MDDL 190.00

7.3.1.5 Maximum Backwater Level at Full Reservoir Level andMaximum Water Level and its Effect, Points to Which

471

Backwater Effect is Felt, Maximum Distance of Such Pointsfrom the Axis of the Structure

The Full Reservoir Level (FRL) and Maximum Water Level (MWL)of the Chasmandva dam have been fixed at 214.00 m and 215.0 mrespectively. The maximum back water level at MWL is 215.0 m and theeffect extends up to a distance of about 6 km from the axis of the dam (atthe periphery of the reservoir) within which no structure of significantimportance has been identified.

7.3.1.6 Saddle along the Reservoir Rim

The entire rim of proposed Chasmandva reservoir is covered with thecontours of value higher than the MWL as such no saddle is proposed alongthe rim of Chasmandva reservoir.

7.3.1.7 Fetch



The direction of wind in Chasmandva reservoir area is mostly fromeast to west. The Nasik IMD station is located near to the Chasmandva damsite. The maximum wind velocity of 13.2 km/hr is experienced in themonth of June and the minimum wind velocity of 4.5 km/hr is experiencedin the month of December. The average velocity of wind is 8.4 km/hr.However, a normal wind velocity of 44 m/sec has been considered. Thefollowing factors are taken into consideration while computing the freeboard requirement:

472


The details of free board requirement for all the six dams arefurnished in para 6.1.5 of Chapter – 6: Design Aspects. The top of the rock-fill portion of the Chasmandva dam has been fixed at 222 m.


Sediment load observations are being carried out by Government ofGujarat at Amba GandD site located on Tan River (a tributary of AurangaRiver) downstream of Chasmandva dam site. The annual suspendedsediment load observed at the GandD site was 0.3831 mm/year/km2

(Average of sediment flow observed from 1983 to 1992) and the totalsediment load including the bed load would be 0.4406 mm/year/km2. Thesedimentation rate observed at the GandD site is much lower than thesiltation rate recommended for the region in the “compendium of Silting ofReservoirs in India” prepared by CWC. This may be due to lessdevelopmental activities in the catchment area of the dam at present.


A sedimentation rate of 9.0 ham/100 sq.km/year has been adopted foranalysis of Chasmandva reservoir. The basis for adopting the value hasalready been explained under Para 7.1.2.1 above.


Considering the inflow sedimentation rate of 9.0 ham/100 km2/yearthe sediment volume at Chasmandva reservoir will be as under:



473

The Chasmandva reservoir is considered as Flood plain-foot hill type and the standard classification is taken as Type II.

7.3.2.4 Sediment Studies – Chasmandva Reservoir



The sediment distribution is worked out for two periods, viz. 50 yearsand 100 years by Empirical Area Reduction method. For this purpose, theFRL 214.00 m is adopted and bed level of the reservoir is considered as170.00 m. The original Elevation-Area-Capacity table for Chasmandvareservoir is given in Table-7.18.

Table-7.18 Original Elevation-Area-Capacity Table for Chasmandva Reservoir

Elevation(m)

Area( ha) Capacity(MCM)

214.00 615.00 83.63211.00 534.00 66.41209.00 480.00 56.27208.00 454.50 51.60205.00 375.00 39.18202.00 285.00 29.31199.00 212.00 21.88196.00 173.00 16.12193.00 138.80 11.45190.00 107.00 7.77188.00 90.20 5.80186.00 66.40 4.24184.00 58.00 3.00182.00 44.00 1.98181.00 37.00 1.58180.00 30.00 1.24179.00 26.00 0.96178.00 22.00 0.72177.00 18.00 0.52176.00 14.00 0.36175.00 10.00 0.25173.00 6.00 0.09

474

Elevation(m)

Area( ha) Capacity(MCM)

172.05 4.09 0.04172.00 4.00 0.04171.00 2.00 0.01170.00 0.00 0.00

[[

The total sediment during 50 and 100 years will get distributed up toand above various elevations as given in the Table-7.19 below.

Table-7.19Distribution of Total Sediment at

Various Elevations of Chasmandva DamReservoir Level Sediment Deposition in MCM

After 50 Years After 100 YearsUp to 171.75 m 0.027 0.038Above 171.75 m 3.827 7.784Up to 176.00 m 0.252 0.367Above 176.00 m 3.602 7.455Up to 190.00 m 1.572 3.099Above 190.00 m 2.282 4.723



The Minimum Draw Down Level (MDDL) can be fixed anywhereabove 176.00 m which is the new zero elevation after 100 years of operationof the reservoir. The plots of revised elevation-area-capacity curve for 50-Year sedimentation and 100 year sedimentation are given in Figure – 7.5and 7.6 respectively:

Revised Elevation-Area-Capacity Curvefor Chasmandva Dam after 50 years

Capacity (MCM)80 60 40 20 0

215 215

210 210

205 205

(m)

200 200

195 195 (m)

Ele

va

Ele

va190 190

475

185 185

180 180

175 175

170 1700 1 2 3 4 5 6


Figure 7.5: Plot of revised elevation area capacity curve for Chasmandva dam after 50 years

Revised Elevation-Area-Capacity Curvefor Chasmandva Dam after 100 years

Capacity (MCM)

80 70 60 50 40 30 20 10 0

210 210

205 205

200 200

Ele

vati

on (

m) 195 195

Ele

vati

on (

m)

190 190

185 185

180 180

175 175

170 1700 50 100 150 200 250 300 350 400 450 500 550 Area

Area (Ha) Volume

Figure 7.6: Revised Elevation-Area-Capacity Curve for Chasmandva Dam after 100 years

Original and revised (after 50 and 100 years) Elevation-Area-Capacitydetails for Chasmandva reservoir are given in Table-7.20 below:


Capacity Table for Chasmandva Reservoir

476


OriginalCapacity

RevisedArea

After 50Years


Years

RevisedArea

After 100Years



214.00 615.00 83.63 615.00 79.78 615.00 75.81211.00 534.00 66.41 526.86 62.63 519.22 58.74209.00 480.00 56.27 471.44 52.65 462.28 48.93208.00 454.50 51.60 445.41 48.06 435.69 44.44205.00 375.00 39.18 364.76 35.93 353.81 32.61202.00 285.00 29.31 274.05 26.38 262.34 23.40199.00 212.00 21.88 200.66 19.29 188.52 16.67196.00 173.00 16.12 161.51 13.86 149.23 11.61193.00 138.00 11.45 127.39 9.54 115.19 7.65190.00 107.00 7.77 95.87 6.20 83.97 4.68188.00 90.20 5.80 79.37 4.45 67.79 3.16186.00 66.40 4.24 55.96 3.10 44.80 2.04184.00 58.00 3.00 48.05 2.06 37.40 1.22182.00 44.00 1.98 34.64 1.24 24.63 0.60181.00 37.00 1.58 27.98 0.93 18.33 0.39180.00 30.00 1.24 21.35 0.68 12.10 0.24179.00 26.00 0.96 17.76 0.49 8.94 0.13178.00 22.00 0.72 14.21 0.33 5.87 0.06177.00 18.00 0.52 10.70 0.20 2.88 0.01176.00 14.00 0.36 7.24 0.11 0.00 0.00175.00 10.00 0.25 3.84 0.06 0.00 0.00174.00 8.00 0.16 2.52 0.03 0.00 0.00173.00 6.00 0.09 1.30 0.01 0.00 0.00172.05 4.09 0.04 0.28 0.00 0.00 0.00172.00 4.00 0.04 0.23 0.00 0.00 0.00171.00 2.00 0.01 0.00 0.00 0.00 0.00

170.00 0.00 0.00 0.00 0.00 0.00 0.00


All the outlets from the reservoir are fixed at an elevation abovethe New Zero Elevation estimated after considering 100 years ofsedimentation. Therefore, the life of the Chasmandva reservoir has beenconsidered as 100 years.

7.3.4 Capacity

477

7.3.4.1 Capacities of Chasmandva Reservoir

SNo.


YearsAfter 100


DSL) 0.36 0.11 0.00

7.3.4.2 Storage

Simulation analysis considering the inflow and various waterdemands to be met from Chasmandva reservoir has been carried out. Basedon the simulation analysis the live storage has been provided so that thedemand of water for various requirements could be met. The dead storagehas been provided so that the functioning of the project would not beaffected even after accumulation of silt over a period of 100 years. Variousstorage details of the proposed Chasmandva reservoir have been mentionedin the Para 7.3.4.1 above.

The monthly minimum storages reserved in Chasmandva reservoir formeeting the water demands towards evaporation losses, environmental anddomestic needs to achieve intended success rates are given in Table-7.21below.

Table-7.21Monthly Minimum Storages Reserved in Chasmandva Reservoir for

Meeting Evaporation Losses, Environmental and Domestic Needs Uni

t: MCM

J J Aug

Sept

ONov

DJ F March

April

May

2 2 2 2 2 8 7 6 5 4 3 2

478

The monthly inflow series and monthly diversion requirementsconsidered for simulation analysis of Chasmandva reservoir for fixing itslive storage are furnished in Appendix 5.5 in Volume – III.


DPR stage Geotechnical investigations were carried out atChasmandva dam site by Engineering Geology Division, Western Region,GSI, Jaipur during the field season 2009-10. A total of 19 number ofexploratory bore holes have been drilled in the different sections of theproposed dam site at Chasmandva. The bore hole core logging aggregating atotal length of 413.75 m has been carried out. These exploratory bore holeswere drilled along the different sections of the proposed dam to know thesub surface geological conditions at the dam site. The basaltic flows ofDeccan Trap form the foundation rock at the dam site. The rock hashorizontal to sub horizontal disposition. The water percolation test results ofthese bore holes indicate that permeability of the rock strata is low. Butcertain sections in bore hole numbers 7, 8, 9, and 11 have higher values ofequivalent permeability. The depth of permeable strata established by thebore holes need to be plugged by grouting between R.D.1280 m toR.D.1780 m (B.H.No.7 to B.H.No.11).

The reservoir appears to be water tight. The report of GSI is atAppendix – 4.5 in Volume – III. Also the periphery of the proposedChasmandva reservoir is covered with the contours of value higher than theMWL.


The simulation study carried out for Chasmandva reservoir for theperiod from 1975 to 2006 indicates that the annual average evaporation lossfrom Chasmandva reservoir is 3.1 MCM with highest evaporation loss as4.0 MCM during the year 1975 and the lowest evaporation loss as 2.0 MCMduring the year 1987. Maximum Monthly evaporation loss is in Octobermonth and least Monthly evaporation loss is in June/December.


479

No flood storage is earmarked for this project. However, fromreservoir routing it is seen that the maximum water level attained was 215.0m and the maximum outflow discharge was 3044 Cumec.


The sub-soil water table will improve due to the impoundment ofwater in the Chasmandva reservoir. In addition, the regulated flows from theChasmandva dam into Tan River to meet environmental needs will increasethe sub soil water level in the adjoining areas even during lean season.


The detailed geological mapping to analyze the problems of reservoirstability and reservoir competency with respect to seepage/leakage of theproposed Chasmandva reservoir could not be carried out due to publichindrance during DPR stage. However, based on type of rock formationsobserved at the periphery of the reservoir, no reservoir rim stabilityproblems are expected.


Area of submergence of Chasmandva reservoir at MWL is 629 ha.


Area of submergence of Chasmandva reservoir at FRL is 615 ha.


The Chasmandva reservoir is a part of net-work of 6 reservoirsproposed under Par-Tapi-Narmada Link Project for diversion of surplus

480

waters of Par, Auranga, Ambica and Purna rivers for en-route irrigation andto take-over part command of Narmada Main Canal. The total submergencearea (cultivated) under the six reservoirs is 2364 ha and the total CCA of theLink project is 232175 ha. Therefore, the Submergence Ratio works out to0.0102.


The land to be acquired is about 615 ha (forest land: 300 ha,cultivable land: 255 ha and other lands including river portion: 60 ha) that iscoming under submergence of Chasmandva reservoir.


Due to creation of Chasmandva reservoir 7 villages will be affected.These villages come under Dharampur taluka of Valsad district and Vansdataluka of Navsari district of Gujarat and Surgana taluka of Nasik district ofMaharashtra. Total 379 households of these villages are likely to beaffected.

(i) Details of Dislocation of Communication (Railways), Road(s),Right of Way, Telegraph Lines etc.) as a Result of the Project

No railway line is coming under the submergence area ofChasmandva reservoir. No major road is coming under Submergence area ofChasmandva dam. No telegraph/ telephone line needs to be dislocated as aresult of the project.


The Engineering Geology Division of GSI, Jaipur vide Letter No.171/G-1/EG/WR/GSI08-09 dated 9th April, 2009 (Annexure – 4.3 inVolume -II) informed that no significant minerals have been reported from

481

the Chasmandva reservoir area, except construction material and a fewminor minerals like zeolites.


As already mentioned under “Chapter – 4: Surveys andInvestigations-Para 4.2.1 Archaeological Survey”, no antiquarianarchaeological remains have been noticed and none of the centrallyprotected monuments are located in the area likely to be submerged due toconstruction of Chasmandva dam.


The rehabilitation plan has already been detailed under Para 7.1.8.3above.









7.3.10 Pisciculture

The submergence area of Chasmandva reservoir is 615 ha andthere is lot of scope for developing fisheries. Considering the water spreadarea of Chasmandva reservoir and the fish production rate indicated above,expected fish production in Chasmandva reservoir will be about 31 tonnesper year which will increase the revenue from the project.

7.3.11 Need and Recommendation for Soil Conservation Measurein the Catchment

482


Step drain


Stone masonry

Check dams

Contour bunding



Pasture development

Social forestry


7.4. Chikkar Reservoir7.4.1. Fixation of Storage and Reservoir Levels - Approach–Criteria

The water availability studies at Jheri, Paikhed, Chasmandva,Chikkar, Dabdar and Kelwan dam sites have been carried out by theHydrological Studies Organisation, CWC, New Delhi as a part of“Hydrological Studies of Par-Tapi-Narmada Link Project”. The Gross andNet Annual Yields at Chikkar dam site as per these studies are as given inTable: 7.22 below.

Table: 7.22 Gross and Net Annual Yields at Chikkar Dam Site

S.No.



The net water availability at Chikkar dam site has been worked outafter subtracting all the consumptive upstream utilizations planned by

483

States. Regeneration from major and medium irrigation projects has beentaken as 10 percent while the same has been ignored in case of minorirrigation projects. The regeneration from domestic and industrial uses hasbeen considered as 80 percent of water diverted for the purpose. The netyield series generated at Chikkar dam site for the period from 1975-76 to2006-07 is at Annexure: 5.16 in Volume - II.

The reservoir simulation study has been carried out for estimating thelive storage capacity of the reservoir that would provide the required yield atspecified reliability. The discharge data is available for a period of 27 yearsfrom 1980 to 2006 at Kudkas G and D site maintained by Government ofGujarat on Khapri River (tributary of Ambica river), which is located U/s ofDabdar dam site. Rainfall – Runoff model has been developed usingdischarge data available at Kudkas G and D site and rainfall for theconcurrent period. Using this Rainfall – Runoff model the gross yield seriesfor the period from 1975-76 to 2006-07 at Chikkar dam site has beendeveloped. The net yield series at the dam site has been generated bysubtracting the net upstream consumptive use from the gross yield seriesand used for simulation analysis.

The simulation analysis has been done using Simulation Programdeveloped using c++. This programme also takes into account the differentreleases from Chikkar reservoir: i) for local domestic and industrial waterdemand, ii) environmental and ecological requirements downstream ofproposed dam site, and iii) diversion to Dabdar reservoir through FeederCanal for further transfer to Par-Tapi-Narmada Link Canal. The result ofthis analysis is at Appendix 5.5 in Volume - IV which gives detailed outputfor the gross capacity of 141.99 MCM.


The dead storage capacity of the Chikkar reservoir has been fixed onthe basis of the guidelines given in “Fixing the capacities of reservoirs –Methods, Part 2 Dead storage, IS 5477 (Part 2): 1994”. The new zeroelevation of the Chikkar reservoir has been worked out as 162.10 m and169.30 m after 50 years and 100 years respectively on the basis ofsedimentation studies. The corresponding capacities at these levels as per

484

the original Area - Capacity table come to 64.64 ha m and 331.90 ha mrespectively. However, Dead Storage Level of the reservoir has beenproposed as 170.00 m (corresponding original capacity of 369.17 ha m) andsluices are proposed to be provided above this level. The details ofsedimentation studies are furnished in Appendix 5.2 in Volume – IV.


The Minimum Draw Down Level (MDDL) of Chikkar reservoir canbe fixed anywhere above 169.30 m which is the new zero elevation after100 years of operation of the reservoir, based on sedimentation studiescarried out by Hydrological Studies Organisation, CWC, New Delhi.Keeping in view the live storage requirement for meeting the Link Canaldemands and power generation, the MDDL of Chikkar reservoir is kept at179.00 m.


Integrated simulation studies carried out for Jheri, Paikhed,Chasmandva, Chikkar, Dabdar and Kelwan reservoirs indicate that theproposed Chikkar reservoir with Full Reservoir Level at 210.00 m will meetvarious planned demands at 100% success rate. Therefore, the FullReservoir Level of Chikkar dam has been kept at 210.00 m.


Maximum Water Level of Chikkar reservoir has been kept as212.0 m and the gates of spillway have been designed to pass design floodof 5649 Cumec.

The Maximum Water Level at Chikkar dam has been fixed as 212.0m. various levels fixed at Chikkar Reservoir are given in Table - 7.23.


Chikkar Reservoir Elevation(m)MWL 212.0FRL 210.00

485

MDDL 179.00

7.4.1.5 Maximum Backwater Level at Full Reservoir Level andMaximum Water Level and its Effect, Points to WhichBackwater Effect is Felt, Maximum Distance of Such Pointsfrom the Axis of the Structure

The Full Reservoir Level (FRL) and Maximum Water Level (MWL)of the Chikkar dam have been fixed at 210.00 m and 212.0 m respectively.The maximum back water level at MWL is 212.0 m and the effect extendsup to a distance of about 11 km from the axis of the dam (at the periphery ofthe reservoir) within which no structure of significant importance has beenidentified.


The entire rim of proposed Chikkar reservoir is covered with thecontours of value higher than the MWL as such no saddle is proposed alongthe rim of Chikkar reservoir.

7.4.1.7 Fetch



The direction of wind in Chikkar reservoir area is mostly from east to

west. The Nasik IMD station is located near to the Chikkar dam site. Themaximum wind velocity of 13.2 km/hr is experienced in the month of Juneand the minimum wind velocity of 4.5 km/hr is experienced in the month ofDecember. The average velocity of wind is 8.4 km/hr. However, a normal

486

wind velocity of 44 m/sec has been considered. The following factors aretaken into consideration while computing the free board requirement:


The details of free board requirement for all the six dams arefurnished in para 6.1.5 of Chapter – 6: Design Aspects. The top of the rock-fill portion of the Chikkar dam has been fixed at 217 m.


Sediment load observations are being carried out by CWC at GadatGandD site located on Ambica River downstream of Chikkar dam site. Theannual suspended sediment load observed at the GandD site was 0.2443mm/year/km2 (Average of sediment flow observed from 1985 to 1993) andthe total sediment load including the bed load would be 0.2810mm/year/km2. The sedimentation rate observed at the GandD site is muchlower than the siltation rate recommended for the region in the“Compendium of Silting of Reservoirs in India” prepared by CWC. Thismay be due to less developmental activities in the catchment area of the damat present.7.4.2.1 Rate of Sedimentation with Basis

A sedimentation rate of 9.0 ham/100 sq.km/year has been adopted foranalysis of Chikkar reservoir. The basis for adopting the value has alreadybeen explained under Para 7.1.2.1 above.


Considering the inflow sedimentation rate of 9.0 ham/100 km2/year thesediment volume at Chikkar reservoir will be as under.


487


The Chikkar reservoir is considered as Flood plain-foot hill type and the standard classification is taken as Type II.

7.4.2.4 Sediment Studies – Chikkar Reservoir



The sediment distribution is worked out for two periods, viz. 50 yearsand 100 years by Empirical Area Reduction method. For this purpose, theFRL 210.00 m is adopted and bed level of the reservoir is considered as152.43 m. The original Elevation-Area-Capacity table for Chikkar reservoiris given in Table-7.24.

Table-7.24 Original Elevation-Area-Capacity Table

for Chikkar Reservoir

Elevation(m)

Area( ha)

Capacity (MCM)

210.00 741.83 141.99

208.00 711.10 127.46

205.00 666.23 106.81

202.00 589.18 87.99

199.00 510.38 71.51

196.00 425.33 57.49

193.00 354.84 45.81

190.00 298.85 36.01

187.00 241.81 27.92

184.00 197.05 21.35

181.00 160.87 15.99

488

Elevation(m)

Area( ha)

Capacity (MCM)

179.00 142.03 12.96

176.00 120.43 9.03

173.00 89.40 5.89170.00 58.50 3.69168.00 47.79 2.63166.00 38.16 1.77164.00 28.59 1.11163.00 24.08 0.84162.50 21.82 0.73162.46 21.62 0.72162.00 19.56 0.62160.00 12.23 0.31159.00 9.22 0.20158.00 6.63 0.12157.50 5.55 0.09157.00 4.46 0.07156.50 3.59 0.05156.00 2.72 0.03155.00 1.41 0.01154.00 0.53 0.00152.43 0.00 0.00

The total sediment during 50 and 100 years will get distributed up toand above various elevations as given in the Table-7.25 below.

Table-7.25Distribution of Total Sediment at Various Elevations of Chikkar DamReservoir Level Sediment Deposition in MCM

After 50 Years After 100 YearsUp to 162.10 m 0.646 0.646Above 162.10 m 12.397 25.181Up to 170.00 m 2.489 3.445Above 170.00 m 10.554 22.482

489

Up to 179.00 m 5.025 8.746Above 179.00 m 8.018 17.081



The Minimum Draw Ddown Level (MDDL) can be fixed anywhereabove 169.30 m which is the new zero elevation after 100 years of operationof the reservoir. The plots of revised elevation-area-capacity curve for 50-Year sedimentation and 100 year sedimentation are given in Figure – 7.7and 7.8 respectively.

Revised Elevation-Area-Capacity Curvefor Chikkar Dam after 50 years

Capacity (MCM)120 100 80 60 40 20 0

212 212

202 202

192 192

(m)

(m)

Ele

vati

on

182 182

Ele

vati

on172 172

162 162

152 1520 100 200 300 400 500 600 700


Figure 7.7: Plot of revised elevation area capacity curve for chikkar dam after 50 years

Revised Elevation-Area-Capacity Curvefor Chikkar Dam after 100 years

Capacity (MCM)120 100 80 60 40 20 0

210 210

200 200

490

190 190

Ele

vati

on (

m)

180 180El

evat

ion(

m)

170170

160 160

150 1500 100 200 300 400 500 600 700 800

Area (Ha) AreaVolume

Figure 7.8: Revised Elevation-Area-Capacity Curve for Chikkar Dam after 100 years

Original and revised (after 50 and 100 years) Elevation-Area-Capacity details for Chikkar reservoir are given in Table-7.26 below:


Capacity Table for Chikkar Reservoir


OriginalCapacity

RevisedArea

After 50Years


50 Years

RevisedArea

After 100Years



210.00 741.83 141.99 741.83 128.95 741.83 116.15208.00 711.10 127.46 696.36 114.52 679.69 101.83205.00 666.23 106.81 645.43 94.40 621.92 82.30202.00 589.18 87.99 564.79 76.25 537.23 64.92199.00 510.38 71.51 483.56 60.54 453.25 50.08196.00 425.33 57.49 396.83 47.35 364.61 37.83193.00 354.84 45.81 325.20 36.54 291.71 28.00190.00 298.85 36.01 268.53 27.65 234.26 20.13187.00 241.81 27.92 211.19 20.47 176.58 13.98184.00 197.05 21.35 166.47 14.81 131.92 9.36181.00 160.87 15.99 130.66 10.36 96.52 5.94179.00 142.03 12.96 112.24 7.94 78.58 4.20176.00 120.43 9.03 91.54 4.88 58.88 2.14173.00 89.40 5.89 61.72 2.60 30.44 0.81

491


OriginalCapacity

RevisedArea

After 50Years


50 Years

RevisedArea

After 100Years



170.00 58.50 3.69 32.38 1.20 2.85 0.33168.00 47.79 2.63 22.91 0.65 0.00 0.00166.00 38.16 1.77 14.72 0.28 0.00 0.00164.00 28.59 1.11 6.79 0.06 0.00 0.00163.00 24.08 0.84 3.18 0.01 0.00 0.00162.50 21.82 0.73 1.41 0.00 0.00 0.00162.10 20.01 0.65 0.00 0.00 0.00 0.00162.00 19.56 062 0.00 0.00 0.00 0.00160.00 12.23 0.31 0.00 0.00 0.00 0.00159.00 9.22 0.20 0.00 0.00 0.00 0.00158.00 6.63 0.12 0.00 0.00 0.00 0.00157.50 5.55 0.09 0.00 0.00 0.00 0.00

157.00 4.46 0.07 0.00 0.00 0.00 0.00156.50 3.59 0.05 0.00 0.00 0.00 0.00156.00 2.72 0.03 0.00 0.00 0.00 0.00155.00 1.41 0.01 0.00 0.00 0.00 0.00154.00 0.53 0.00 0.00 0.00 0.00 0.00152.43 0.00 0.00 0.00 0.00 0.00 0.00


All the outlets from the reservoir are fixed at an elevation abovethe New Zero Elevation estimated after considering 100 years ofsedimentation. Therefore, the life of the Chikkar reservoir has beenconsidered as 100 years.

7.4.4 Capacity 7.4.4.1 Capacities of Chikkar Reservoir

SNo.


YearsAfter 100

Years1 Gross storage capacity 141.99 128.95 116.152 Live storage capacity 129.03 121.01 111.953 Storage capacity at MDDL 12.96 7.94 4.204 Dead storage capacity (at 3.69 1.20 0.33

492

DSL)

7.4.4.2 Storage

Simulation analysis considering the inflow and various waterdemands to be met from Chikkar reservoir has been carried out. Based onthe simulation analysis the live storage has been provided so that thedemand of water for various requirements could be met. The dead storagehas been provided so that the functioning of the project would not beaffected even after accumulation of silt over a period of 100 years. Variousstorage details of the proposed Chikkar reservoir have been mentioned inthe Para 7.4.4.1 above.

The monthly minimum storages reserved in Chikkar reservoir formeeting the water demands towards evaporation losses, environmental anddomestic needs to achieve intended success rates are given in Table-7.27below:

Table-7.27Monthly Minimum Storages Reserved in Chikkar Reservoir for

Meeting Evaporation Losses, Environmental and Domestic Needs Unit:

MCM

J J Aug

Sept

ONov

DJ F March

April

May

1 1 1 1 1 8 7 6 5 4 3 2

The monthly inflow series and monthly diversion requirementsconsidered for simulation analysis of Chikkar reservoir for fixing its livestorage are furnished in Appendix 5.5 in Volume – IV.


Preliminary Geotechnical Investigations were carried out at the damsite by GSI, Western Region, and Jaipur at Feasibility stage of Par-Tapi-Narmada Link Project during 1993-94. As per these investigations the

493

foundation rocks at the dam site are sub-horizontal sequence of lava flowsof Deccan traps. The contacts zone between the successive lava flows aremoderately to highly weathered and marked by presence of flow breccias,with predominance of amygdule. Hence, consolidated grouting shall beneeded to make the strata monolithic and to improve their strength andimperviousness.

The report of GSI is at Appendix-4.8 in Volume-III. Also theperiphery of the proposed Chikkar reservoir is covered with the contours ofvalue higher than the MWL.


The simulation study carried out for Chikkar reservoir for the periodfrom 1975 to 2006 indicates that the annual average evaporation loss fromChikkar reservoir is 6.4 MCM with highest evaporation loss as 6.9 MCMduring the years 1994, 2003 and 2005 and the lowest evaporation loss as 4.5MCM during the year 1987. Maximum Monthly evaporation loss is inDecember month and least Monthly evaporation loss is in June.


No flood storage is earmarked for this project. However, fromreservoir routing it is seen that the maximum water level attained was 212.0m and the maximum outflow discharge was 5226 Cumec.


The sub-soil water table will improve due to the impoundment ofwater in the Chikkar reservoir. In addition, the regulated flows from theChikkar dam into Ambica River to meet environmental needs will increasethe sub soil water level in the adjoining areas even during lean season.


494

The detailed geological mapping to analyze the problems of reservoirstability and reservoir competency with respect to seepage/leakage of theproposed Chikkar reservoir could not be carried out due to public hindranceduring DPR stage. However, preliminary Geotechnical investigations werecarried out at the dam site by GSI, Western Region, Jaipur at Feasibilitystage of Par-Tapi-Narmada Link Project during 1993-94. The entirereservoir area is covered by the Deccan basalts with moderate relief. Therock type encountered is a sub horizontal sequence of lava flows. Thereservoir rim is expected to be stable and may not pose any stabilityproblems

The reservoir area appears to be water tight with no perceptible shearor fault zone criss- crossing the area.


Area of submergence of Chikkar reservoir at MWL is 760 ha.


Area of submergence of Chikkar reservoir at FRL is 742 ha. 7.4.7.3 Submergence Ratio - Submerged (Cultivated) Area/CCA

The Chikkar reservoir is a part of net-work of 6 reservoirs proposedunder Par-Tapi-Narmada Link Project for diversion of surplus waters of Par,Auranga, Ambica and Purna rivers for en-route irrigation and to take-overpart command of Narmada Main Canal. The total submergence area(cultivated) under the six reservoirs is 2364 ha and the total CCA of theLink project is 232175 ha. Therefore, the Submergence Ratio works out to0.0102.


495

The land to be acquired is about 742 ha (forest land: 300 ha, cultivable land:332 ha and other lands including river portion: 110 ha) that is coming undersubmergence of Chikkar reservoir.


Due to creation of Chikkar reservoir 9 villages will be affected. Thesevillages come under Ahwa taluka of The Dangs district of Gujarat. Total 345households of these villages are likely to be affected.

(i) Details of Dislocation of Communication (Railways), Road(s),Right of Way, Telegraph Lines etc.) as a result of the Project

No railway line is coming under the submergence area of Chikkarreservoir. The State Highway connecting Waghai and Saputara is comingunder Submergence area of Chikkar dam. The power and telephone lines ofabout 10 km length connecting Baj-Lahen-Dabdar villages to be dislocatedas a result of the project.


The Engineering Geology Division of GSI, Jaipur vide Letter No.171/G-1/EG/WR/GSI08-09 dated 9th April, 2009 (Annexure – 4.3 inVolume -II) informed that no significant minerals have been reported fromthe Chikkar reservoir area, except construction material and a few minorminerals like zeolites.


As already mentioned under “Chapter – 4: Surveys andInvestigations-Para 4.2.1 Archaeological Survey”, no antiquarianarchaeological remains have been noticed and none of the centrallyprotected monuments are located in the area likely to be submerged due toconstruction of Chikkar dam.

496










These facilities will ensure tourism development in the area. Thewater-fall located just downstream of the dam site further enhances thetourism potential.

7.4.10 Pisciculture

The submergence area of Chikkar reservoir is 742 ha and there islot of scope for developing fisheries.

Considering the water spread area of Chikkar reservoir and the fishproduction rate indicated above, expected fish production in Chikkarreservoir will be about 37 tonnes per year which will increase the revenuefrom the project. 7.4.11 Need and Recommendation for Soil Conservation Measure

in the Catchment

The chances of soil erosion, if any can be prevented/minimized by adoptingfollowing measures:

Step drain


497

Stone masonry

Check dams

Contour bunding



Pasture development

Social forestry


7.5. Dabdar Reservoir7.5.1. Fixation of Storage and Reservoir Levels - Approach–Criteria

The water availability studies at Jheri, Paikhed, Chasmandva,Chikkar, Dabdar and Kelwan dam sites have been carried out by theHydrological Studies Organisation, CWC, New Delhi as a part of“Hydrological Studies of Par-Tapi-Narmada Link Project”. The Gross andNet Annual Yields at Dabdar dam site as per these studies are as given inTable: 5.28 below.

Table: 5.28 Gross and Net Annual Yields at Dabdar Dam Site

S.No.



The net water availability at Dabdar dam site has been worked outafter subtracting all the consumptive upstream utilizations planned byStates. Regeneration from major and medium irrigation projects has beentaken as 10 percent while the same has been ignored in case of minorirrigation projects. The regeneration from domestic and industrial uses hasbeen considered as 80 percent of water diverted for the purpose. The netyield series generated at Dabdar dam site for the period from 1975-76 to2006-07 is at Annexure: 5.17 in Volume - II.

498

The reservoir simulation study has been carried out for estimating thelive storage capacity of the reservoir that would provide the required yield atspecified reliability. The discharge data is available for a period of 27 yearsfrom 1980 to 2006 at Kudkas G and D site maintained by Government ofGujarat on Khapri River (tributary of Ambica river), which is located U/s ofDabdar dam site. Rainfall – Runoff model has been developed usingdischarge data available at Kudkas G and D site and rainfall for theconcurrent period. Using this Rainfall – Runoff model the gross yield seriesfor the period from 1975-76 to 2006-07 at Dabdar dam site has beendeveloped. The net yield series at the dam site has been generated bysubtracting the net upstream consumptive use from the gross yield seriesand used for simulation analysis.

The simulation analysis has been done using Simulation Programdeveloped using c++. This programme also takes into account the differentreleases from Dabdar reservoir: i) for local domestic and industrial waterdemand, ii) environmental and ecological requirements downstream ofproposed dam site, and iii) en-route irrigation requirement of DabdarFeeder Canal and iv) releases into Dabdar Feeder Canal, after powergeneration, for further transfer to Par-Tapi-Narmada Link Canal. The resultof this analysis is at Appendix 5.5 in Volume - IV which gives detailedoutput for the gross capacity of 222.38 MCM.


The dead storage capacity of the Dabdar reservoir has been fixed onthe basis of the guidelines given in “Fixing the capacities of reservoirs –Methods, Part 2 Dead storage, IS 5477 (Part 2): 1994”.

The new zero elevation of the Dabdar reservoir has been worked outas 119.90 m and 126.90 m after 50 years and 100 years respectively on thebasis of sedimentation studies. The corresponding capacities at these levelsas per the original Area - Capacity table come to 70.07 ha m and 424.28 ham respectively. However, Dead Storage Level of the reservoir has beenproposed as 127.00 m (corresponding original capacity of 432.16 ha m) andsluices are proposed to be provided above this level. The details ofsedimentation studies are furnished in Appendix 5.2 in Volume – IV.

499


The Minimum Draw Down Level (MDDL) of Dabdar reservoir canbe fixed anywhere above 126.90 m which is the new zero elevation after100 years of operation of the reservoir, based on sedimentation studiescarried out by Hydrological Studies Organisation, CWC, New Delhi.Keeping in view the live storage requirement for meeting the Link Canaldemands and power generation, the MDDL of Dabdar reservoir is kept at139.00 m.


Integrated simulation studies carried out for Jheri, Paikhed,Chasmandva, Chikkar, Dabdar and Kelwan reservoirs indicate that theproposed Dabdar reservoir with Full Reservoir Level at 169.00 m will meetvarious planned demands at 100% success rate. Therefore, the FullReservoir Level of Dabdar dam has been kept at 169.00 m.


Maximum Water Level of Dabdar reservoir has been kept as 170.0m and the gates of spillway have been designed to pass design flood of 6683Cumec.

The Maximum Water Level at Dabdar dam has been fixed as 170.0 m.Various levels fixed at Dabdar Reservoir are given in Table - 7.29.


Dabdar Reservoir Elevation(m)MWL 170.00FRL 169.00MDDL 139.00


500


The Full Reservoir Level (FRL) and Maximum Water Level (MWL)of the Dabdar dam have been fixed at 169.00 m and 170.0 m respectively.The maximum back water level at MWL is 170.0 m and the effect extendsup to a distance of about 11 km from the axis of the dam (at the periphery ofthe reservoir) within which no structure of significant importance has beenidentified.


The entire rim of proposed Dabdar reservoir is covered with thecontours of value higher than the MWL as such no saddle is proposed alongthe rim of Dabdar reservoir.

7.5.1.7 Fetch



The direction of wind in Dabdar reservoir area is mostly from east towest. The Nasik IMD station is located near to the Dabdar dam site. Themaximum wind velocity of 13.2 km/hr is experienced in the month of Juneand the minimum wind velocity of 4.5 km/hr is experienced in the month ofDecember. The average velocity of wind is 8.4 km/hr. However, a normalwind velocity of 44 m/sec has been considered. The following factors aretaken into consideration while computing the free board requirement:

(a) Wave characteristics i.e. wave height and wave length; (b)Upstream slope of the dams and roughness of the pitching;(c) Height of wind setup above the still water level.

501

The details of free board requirement for all the six dams are furnished inpara 6.1.5 of Chapter – 6: Design Aspects. The top of the rock-fill portion ofthe Dabdar dam has been fixed at 177 m.


Sediment load observations are being carried out by CWC at GadatGandD site located on Ambica River downstream of Dabdar dam site. Theannual suspended sediment load observed at the GandD site was 0.2443mm/year/km2 (Average of sediment flow observed from 1985 to 1993) andthe total sediment load including the bed load would be 0.2810mm/year/km2. The sedimentation rate observed at the GandD site is muchlower than the siltation rate recommended for the region in the“Compendium of Silting of Reservoirs in India” prepared by CWC. Thismay be due to less developmental activities in the catchment area of the damat present.


A sedimentation rate of 9.0 ham/100 sq.km/year has been adopted foranalysis of Dabdar reservoir. The basis for adopting the value has alreadybeen explained under Para 7.1.2.1 above.


Considering the inflow sedimentation rate of 9.0 ham/100 km2/year thesediment volume at Dabdar reservoir will be as under.



The Dabdar reservoir is considered as Flood plain-foot hill type and the standard classification is taken as Type II.

502

7.5.2.4 Sediment Studies – Dabdar Reservoir



The sediment distribution is worked out for two periods, viz. 50 yearsand 100 years by Empirical Area Reduction method. For this purpose, theFRL 169.00 m is adopted and bed level of the reservoir is considered as112.00 m. The original Elevation-Area-Capacity table for Dabdar reservoiris given in Table-7.30.


for Dabdar ReservoirElevation

(m)Area( ha) Capacity

( MCM)

169.00 1248.77 222.38

166.00 1204.37 185.58

163.00 1036.71 152.00

160.00 826.05 124.12

157.00 740.22 100.63

154.00 636.30 80.01

151.00 499.61 63.01

148.00 412.78 49.34

145.00 349.75 37.92

142.00 273.08 28.60

139.00 213.25 21.32

136.00 173.90 15.53

133.00 139.29 10.84

130.00 108.84 7.13128.00 88.43 5.16126.00 70.14 3.57125.00 61.80 2.92

503

Elevation(m)

Area( ha) Capacity( MCM)

124.00 53.95 2.34123.00 46.63 1.83122.00 39.87 1.40121.00 33.62 1.04120.38 30.07 0.84120.00 27.90 0.73119.50 24.61 0.60119.00 21.31 0.48118.00 15.60 0.30117.00 10.79 0.17116.00 6.86 0.08115.00 3.82 0.03114.00 1.05 0.00113.00 0.01 0.00112.00 0.00 0.00

The total sediment during 50 and 100 years will get distributed up toand above various elevations as given in the Table-7.31below:

Table-7.31Distribution of Total Sediment at Various Elevations of Dabdar Dam

Reservoir level Sediment Deposition in MCMAfter 50 Years After 100 Years

Up to 119.90 m 0.701 0.702Above 119.90 m 18.748 38.698Up to 127.00 m 3.019 4.321Above 127.00 m 16.429 35.079Up to 139.00 m 7.994 14.950Above 139.00 m 11.455 24.450



The Minimum Draw Down Level (MDDL) can be fixed anywhereabove 126.90 m which is the new zero elevation after 100 years of operationof the reservoir.

504

The plots of revised elevation-area-capacity curve for 50-Yearsedimentation and 100 year sedimentation are given in Figure – 7.9 and 7.10respectively.

Revised Elevation-Area-Capacity Curvefor Dabdar Dam after 50 years

Capacity (MCM)

200 150 100 50 0

162 162

152 152

(m)

(m)

Ele

vati

on

142 142

Ele

vati

on

132 132

122 122

112 1120 200 400 600 800 1000 1200

Area (Ha)AreaVolume

Figure 7.9: Plot of revised elevation area capacity curve for Dabdar dam after 50 years

Revised Elevation-Area-Capacity Curvefor Dabdar Dam after 100 years

Capacity (MCM)150 100 50 0

162 162

152 152

505

Ele

vati

on (

m)

142 142

Ele

vati

on (

m)

132 132

122 122

112 1120 200 400 600 800 1000 1200


Figure 7.10: Revised Elevation-Area-Capacity Curve for Dabdar Dam after 100 years

Original and revised (after 50 and 100 years) Elevation-Area-Capacity details for Dabdar reservoir are given in Table-7.32 below:


Capacity Table for Dabdar Reservoir


OriginalCapacity

RevisedArea

After 50Years


50 Years

RevisedArea

After 100Years



169.00 1248.77 222.38 1248.77 202.93 1248.77 182.98166.00 1204.37 185.58 1178.47 166.39 1149.08 146.74163.00 1036.71 152.00 1003.40 133.70 965.61 115.05160.00 826.05 124.12 788.05 106.88 744.94 89.45157.00 740.22 100.63 699.01 84.59 652.25 68.50154.00 636.30 80.01 592.88 65.23 543.62 50.58151.00 499.61 63.01 454.75 49.56 403.87 36.41148.00 412.78 49.34 367.13 37.25 315.34 25.64145.00 349.75 37.92 303.86 27.20 251.81 17.15142.00 273.08 28.60 227.47 19.25 175.73 10.76139.00 213.25 21.32 168.40 13.33 117.52 6.38136.00 173.90 15.53 130.29 8.86 80.82 3.41133.00 139.29 10.84 97.41 5.45 49.90 1.46130.00 108.84 7.13 69.20 2.96 24.24 0.36128.00 88.43 5.16 50.60 1.77 7.68 0.04127.00 79.29 4.32 42.50 1.34 0.68 0.00

506


OriginalCapacity

RevisedArea

After 50Years


50 Years

RevisedArea

After 100Years



126.00 70.14 3.57 34.39 0.92 0.00 0.00125.00 61.80 2.92 27.21 0.62 0.00 0.00124.00 53.95 2.34 20.59 0.38 0.00 0.00123.00 46.63 1.83 14.60 0.20 0.00 0.00122.00 39.87 1.40 9.26 0.08 0.00 0.00121.00 33.62 1.04 4.55 0.01 0.00 0.00120.38 30.07 0.84 0.00 0.00 0.00 0.00120.00 27.90 0.73 0.00 0.00 0.00 0.00119.90 27.24 0.70 0.00 0.00 0.00 0.00119.50 24.61 0.60 0.00 0.00 0.00 0.00119.00 21.31 0.48 0.00 0.00 0.00 0.00

118.80 20.17 0.44 0.00 0.00 0.00 0.00118.00 15.60 0.29 0.00 0.00 0.00 0.00117.00 10.79 0.17 0.00 0.00 0.00 0.00116.00 6.86 0.08 0.00 0.00 0.00 0.00115.00 3.82 0.03 0.00 0.00 0.00 0.00114.00 1.05 0.00 0.00 0.00 0.00 0.00113.00 0.01 0.00 0.00 0.00 0.00 0.00112.00 0.00 0.00 0.00 0.00 0.00 0.00


All the outlets from the reservoir are fixed at an elevation abovethe New Zero Elevation estimated after considering 100 years ofsedimentation. Therefore, the life of the Dabdar reservoir has beenconsidered as 100 years.

7.5.4 Capacity 7.5.4.1 Capacities of Dabdar ReservoirSNo.


YearsAfter 100

Years

507

1 Gross storage capacity 222.38 202.93 182.982 Live storage capacity 201.06 189.60 176.603 Storage capacity at MDDL 21.32 13.33 6.384 Dead storage capacity (at

DSL) 4.32 1.34 0.00

7.5.4.2 Storage

Simulation analysis considering the inflow and various waterdemands to be met from Dabdar reservoir has been carried out. Based on thesimulation analysis the live storage has been provided so that the demand ofwater for various requirements could be met. The dead storage has beenprovided so that the functioning of the project would not be affected evenafter accumulation of silt over a period of 100 years. Various storage detailsof the proposed Dabdar reservoir have been mentioned in the Para 7.5.4.1above.

The monthly minimum storages reserved in Dabdar reservoir formeeting the water demands towards evaporation losses, environmental anddomestic needs to achieve intended success rates are given in Table-7.33below:

Table-7.33Monthly Minimum Storages Reserved in Dabdar Reservoir for Meeting

Evaporation Losses, Environmental and Domestic Needs Unit: MCM

J J Aug

Sept

ONov

DJ F March

April

May

2 2 2 2 1 15

1 1 1 6 5 3

The monthly inflow series and monthly diversion requirementsconsidered for simulation analysis of Dabdar reservoir for fixing its livestorage are furnished in Appendix 5.5 in Volume – III.


508

Preliminary Geotechnical Investigations were carried out at the damsite by GSI, Western Region, Jaipur at Feasibility stage of Par-Tapi-Narmada Link Project during 1993-94. As per these investigations thefoundation rocks at the dam site are Deccan traps. The bed rock constitutingthe foundation are a sequence of lava flows, which comprises amygdaloidal,dense, perphyritic basalt and flow breccias with horizontal to sub horizontaldips. The reservoir appears to be water tight.

The reports of GSI are at Appendix-4.2 and 4.4 in Volume-III. Alsothe periphery of the proposed Dabdar reservoir is covered with the contoursof value higher than the MWL.


The simulation study carried out for Dabdar reservoir for the periodfrom 1975 to 2006 indicates that the annual average evaporation loss fromDabdar reservoir is 6.6 MCM with highest evaporation loss as 8.6 MCMduring the years 1975 and 1983 and the lowest evaporation loss as 3.7MCM during the year 1987. Maximum Monthly evaporation loss is inOctober month and least Monthly evaporation loss is in July.




The sub-soil water table will improve due to the impoundment ofwater in the Dabdar reservoir. In addition, the regulated flows from theDabdar dam into Khapri River to meet environmental needs will increasethe sub soil water level in the adjoining areas even during lean season.

509


The detailed geological mapping to analyze the problems of reservoirstability and reservoir competency with respect to seepage/leakage of theproposed Dabdar reservoir could not be carried out due to public hindranceduring DPR stage. However, preliminary Geotechnical investigations werecarried out at the dam site by GSI, Western Region, Jaipur at Feasibilitystage of Par-Tapi-Narmada Link Project during 1993-94. The entirereservoir area is covered by the Deccan traps. The rock type encountered issequence of lava flows. In view of the rock type encountered at theperiphery of the reservoir, no stability problem of reservoir rim is expected.

The reservoir area appears to be water tight with no perceptible shearor fault zone criss- crossing the area.


Area of submergence of Dabdar reservoir at MWL is 1271 ha.


Area of submergence of Dabdar reservoir at FRL is 1249 ha. 7.5.7.3 Submergence Ratio - Submerged (Cultivated) Area/CCA

The Dabdar reservoir is a part of net-work of 6 reservoirs proposedunder Par-Tapi-Narmada Link Project for diversion of surplus waters of Par,Auranga, Ambica and Purna rivers for en-route irrigation and to take-overpart command of Narmada Main Canal. The total submergence area(cultivated) under the six reservoirs is 2364 ha and the total CCA of theLink project is 232175 ha. Therefore, the Submergence Ratio works out to0.0102.


510

The land to be acquired is about 1249 ha (forest land: 614 ha,cultivable land: 482 ha and other lands including river portion: 153 ha) thatis coming under submergence of Dabdar reservoir.


Due to creation of Dabdar reservoir 11 villages will be affected.These villages come under Ahwa taluka of The Dangs district of Gujarat.Total 563 households of these villages are likely to be affected.

(i) Details of Dislocation of Communication (Railways), Road(s), Rightof Way, Telegraph Lines etc.) as a Result of the Project

No railway line is coming under the submergence area of Dabdarreservoir. The State Highway connecting Bilimora and Ahwa is comingunder Submergence area of Dabdar dam. The power and telephone lines ofabout 12 km length connecting Waghai-Pimpri villages to be dislocated as aresult of the project.


The Engineering Geology Division of GSI, Jaipur vide Letter No.171/G-1/EG/WR/GSI08-09 dated 9th April, 2009 (Annexure – 4.3 inVolume -II) informed that no significant minerals have been reported fromthe Dabdar reservoir area, except construction material and a few minorminerals like zeolites.


As already mentioned under “Chapter – 4: Surveys andInvestigations-Para 4.2.1 Archaeological Survey”, no antiquarianarchaeological remains have been noticed and none of the centrallyprotected monuments are located in the area likely to be submerged due toconstruction of Dabdar dam.

511











7.5.10 Pisciculture

The submergence area of Dabdar reservoir is 1249 ha and there islot of scope for developing fisheries.

Considering the water spread area of Dabdar reservoir and the fishproduction rate indicated above, expected fish production in Dabdarreservoir will be about 62 tonnes per year which will increase the revenuefrom the project.

7.5.11 Need and Recommendation for Soil Conservation Measuresin the Catchment


Step drain

512


Stone masonry

Check dams

Contour bunding



Pasture development

Social forestry


7.6. Kelwan Reservoir7.6.1. Fixation of Storage and Reservoir Levels - Approach–Criteria

The water availability studies at Jheri, Paikhed, Chasmandva,Chikkar, Dabdar and Kelwan dam sites have been carried out by theHydrological Studies Organisation, CWC, New Delhi as a part of“Hydrological Studies of Par-Tapi-Narmada Link Project”. The Gross andNet Annual Yields at Kelwan dam site as per these studies are as given inTable: 7.34 below.

Table: 7.34 Gross and Net Annual Yields at Kelwan Dam Site

S.No.



The net water availability at Kelwan dam site has been worked outafter subtracting all the consumptive upstream utilizations planned byStates. Regeneration from major and medium irrigation projects has beentaken as 10 percent while the same has been ignored in case of minorirrigation projects. The regeneration from domestic and industrial uses hasbeen considered as 80 percent of water diverted for the purpose. The net

513

yield series generated at Kelwan dam site for the period from 1975-76 to2006-07 is at Annexure: 5.18 in Volume - II.

The gauge and discharge data of the Kalibel GandD site maintainedby Government of Gujarat is available from the year 1962 to 2000 exceptfor the years 1979, 80, 91, 92, 93, 94, 95, 96 and 1999. The site is locatedjust upstream of the Kelwan dam site. Therefore, the yield series at Kelwandam sites have been generated from year 1975, on catchment areaproportionate basis, using observed data after duly checking the consistency.The inconsistent data and gaps have been filled by using rainfall runoffmodeling. The yield series has been further extended beyond year 2000using rainfall runoff modeling. The yield series from 1975 to 2006 has usedfor working out the water availability at the Kelwan dam site.

The simulation analysis has been done using Simulation Programdeveloped using c++. This programme also takes into account the differentreleases from Kelwan reservoir: i) for local domestic and industrial waterdemand, ii) environmental and ecological requirements downstream ofproposed dam site, and iii) en-route irrigation requirement of KelwanFeeder Canal and iv) releases into Kelwan Feeder Canal, after powergeneration, for further transfer to Par-Tapi-Narmada Link Canal. The resultof this analysis is at Appendix 5.5 in Volume - IV which gives detailedoutput for the gross capacity of 282.17 MCM.


The dead storage capacity of the Kelwan reservoir has been fixed onthe basis of the guidelines given in “Fixing the capacities of reservoirs –Methods, Part 2 Dead storage, IS 5477 (Part 2): 1994”.

The new zero elevation of the Kelwan reservoir has been worked out

as 122.20 m and 128.20 m after 50 years and 100 years respectively on thebasis of sedimentation studies. The corresponding capacities at these levelsas per the original Area - Capacity table come to 125.05 ha m and 651.28 ham respectively. However, Dead Storage Level of the reservoir has beenproposed as 128.20 m (corresponding original capacity of 651.28 ha m) andsluices are proposed to be provided above this level. The details ofsedimentation studies are furnished in Appendix 5.2 in Volume – IV.

514


The Minimum Draw Down Level (MDDL) of Kelwan reservoir canbe fixed anywhere above 128.20 m which is the new zero elevation after100 years of operation of the reservoir, based on sedimentation studiescarried out by Hydrological Studies Organisation, CWC, New Delhi.Keeping in view the live storage requirement for meeting the Link Canaldemands and power generation, the MDDL of Kelwan reservoir is kept at136.00 m.


Integrated simulation studies carried out for Jheri, Paikhed,Chasmandva, Chikkar, Dabdar and Kelwan reservoirs indicate that theproposed Kelwan reservoir with Full Reservoir Level at 164.00 m will meetvarious planned demands at 100% success rate. Therefore, the FullReservoir Level of Kelwan dam has been kept at 164.00 m.


Maximum Water Level of Kelwan reservoir has been kept as166.00 m and the gates of spillway have been designed to pass design floodof 7979 Cumec.

The Maximum Water Level at Kelwan dam has been fixed as 166.00m. Various levels fixed at Kelwan Reservoir are given in Table - 7.35.


Kelwan Reservoir Elevation(m)MWL 166.00FRL 164.00MDDL 136.00


515


The Full Reservoir Level (FRL) and Maximum Water Level (MWL)of the Kelwan dam have been fixed at 164.00 m and 166.00 m respectively.The maximum back water level at MWL is 166.00 m and the effect extendsup to a distance of about 24 km from the axis of the dam (at the periphery ofthe reservoir) within which no structure of significant importance has beenidentified.


The entire rim of proposed Kelwan reservoir is covered with thecontours of value higher than the MWL as such no saddle is proposed alongthe rim of Kelwan reservoir.

7.6.1.7 Fetch



The direction of wind in Kelwan reservoir area is mostly from east towest. The Nasik IMD station is located near to the Kelwan dam site. Themaximum wind velocity of 13.2 km/hr is experienced in the month of Juneand the minimum wind velocity of 4.5 km/hr is experienced in the month ofDecember. The average velocity of wind is 8.4 km/hr. However, a normalwind velocity of 44 m/sec has been considered. The following factors aretaken into consideration while computing the free board requirement:

(a) Wave characteristics i.e. wave height and wave length; (b)Upstream slope of the dam and roughness of the pitching;(c) Height of wind setup above the still water level.

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The details of free board requirement for all the six dams arefurnished in para 6.1.5 of Chapter – 6: Design Aspects. The top of the rock-fill portion of the Kelwan dam has been fixed at 174.0 m.


Sediment load observations are being carried out by CWC at MahuvaGandD site located on Purna River downstream of Kelwan dam site. Theannual suspended sediment load observed at the GandD site was 0.3693mm/year/km2 and the total sediment load including the bed load would be0.4247 mm/year/km2. The sedimentation rate observed at the GandD site ismuch lower than the siltation rate recommended for the region in the“Compendium of Silting of Reservoirs in India” prepared by CWC. Thismay be due to less developmental activities in the catchment area of the damat present.


A sedimentation rate of 9.0 ham/100 sq.km/year has been adopted foranalysis of Kelwan reservoir. The basis for adopting the value has alreadybeen explained under Para 7.1.2.1 above.


Considering the inflow sedimentation rate of 9.0 ham/100 km2/year thesediment volume at Kelwan reservoir will be as under:



The Kelwan reservoir is considered as Flood plain-foot hill type and the standard classification is taken as Type II.

7.6.2.4 Sediment Studies – Kelwan Reservoir

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The sediment distribution is worked out for two periods, viz. 50 yearsand 100 years by Empirical Area Reduction method. For this purpose, theFRL 164.00 m is adopted and bed level of the reservoir is considered as115.27 m. The original Elevation-Area-Capacity table for Kelwan reservoiris given in Table-7.36:


for Kelwan ReservoirElevation (m) Revised Area(ha) Capacity

(MCM)164.00 1628.85 282.16163.00 1559.22 266.22161.00 1453.06 236.11158.00 1280.42 195.13155.00 1150.00 158.69152.00 1007.49 126.36149.00 850.95 98.51146.00 704.09 75.22143.00 624.75 55.30140.00 488.00 38.65138.00 344.07 30.37136.00 304.78 23.89134.00 268.72 18.16132.00 215.59 13.32130.00 180.00 9.37128.00 135.19 6.23126.00 95.00 3.94125.00 83.00 3.05124.00 70.00 2.29123.00 55.00 1.66122.00 47.00 1.15121.00 34.00 0.75120.00 26.00 0.45119.00 18.00 0.23

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Elevation (m) Revised Area(ha) Capacity(MCM)

118.50 14.00 0.15118.00 10.00 0.12117.94 9.25 0.09117.75 8.50 0.09117.50 7.00 0.07117.00 4.00 0.05116.00 0.90 0.02115.27 0 0.00


Table-7.37Distribution of Total Sediment at Various Elevations of Kelwan Dam

Reservoir Level Sediment Deposition in MCMAfter 50 Years After 100 Years

Up to 122.20 m 1.25 1.26Above 122.20 m 28.42 57.99Up to 128.20 m 4.70 6.51Above 128.20 m 24.97 52.74Up to 136.00 m 10.29 18.33Above 136.00 m 19.38 40.92

The new zero elevation will be as follows.


The Minimum Draw Down Level (MDDL) can be fixed anywhereabove 128.20 m which is the new zero elevation after 100 years of operationof the reservoir.

The plots of revised elevation-area-capacity curve for 50-Yearsedimentation and 100 year sedimentation are given in Figure – 7.11 and7.12 respectively:

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Revised Elevation-Area-Capacity Curvefor Kelwan Dam after 50 years

Capacity (MCM)250 200 150 100 50 0

160 160

155 155

150 150

(m) 145 145

(m)

Ele

vati

on

140 140

Ele

vati

on

135 135

130 130

125 125

120 120

115 1150 200 400 600 800 1000 1200 1400 1600


Figure 7.11: Plot of revised elevation area capacity curve for Kelwan dam after 50 years

Revised Elevation-Area-Capacity Curvefor Kelwan Dam after 100 years

Capacity (MCM)

250 200 150 100 50 0165 165

160 160

155 155

150 150

Ele

vati

on (

m)

145 145

Ele

vati

on (

m)

140 140

135 135

130 130

125 125

120 120

115 1150 200 400 600 800 1000 1200 1400 1600


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Figure 7.12: Revised Elevation-Area-Capacity Curve for Kelwan Dam after 100 years

Original and revised (after 50 and 100 years) Elevation-Area-Capacity details for Kelwan reservoir are given in Table-7.38 below:


Capacity Table for Kelwan Reservoir


OriginalCapacity

RevisedArea

After 50Years


50 Years

RevisedArea

After 100Years



164.00 1628.85 282.17 1628.85 252.50 1628.85 222.91163.00 1559.22 266.23 1527.62 236.67 1492.49 207.20161.00 1453.06 236.12 1404.68 207.35 1350.89 178.76158.00 1280.42 195.14 1218.58 168.02 1149.82 141.27155.00 1150.00 158.70 1079.94 133.56 1002.05 109.00152.00 1007.49 126.36 932.11 103.40 848.30 81.27149.00 850.95 98.52 772.26 77.87 684.78 58.31146.00 704.09 75.23 623.68 56.96 534.28 40.05143.00 624.75 55.31 543.97 39.46 454.15 25.24140.00 488.00 38.66 408.06 25.22 319.19 13.68138.00 344.07 30.38 265.34 18.53 177.81 8.75136.00 304.78 23.89 227.77 13.60 142.16 5.56134.00 268.72 18.16 193.95 9.39 110.83 3.03132.00 215.59 13.33 143.61 6.02 63.58 1.64130.00 180.00 9.38 111.37 3.48 35.07 0.31128.20 137.43 6.51 74.62 1.85 0.00 0.00128.00 135.19 6.24 70.54 1.67 0.00 0.00127.00 115.10 4.99 52.69 1.06 0.00 0.00126.00 95.00 3.94 35.04 0.62 0.00 0.00125.00 83.00 3.05 25.68 0.32 0.00 0.00124.75 79.75 2.85 23.13 0.25 0.00 0.00124.63 78.13 2.75 21.86 0.23 0.00 0.00124.50 76.50 2.65 20.59 0.20 0.00 0.00124.00 70.00 2.29 15.55 0.11 0.00 0.00123.00 55.00 1.66 3.69 0.01 0.00 0.00122.20 48.60 1.25 0.00 0.00 0.00 0.00

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OriginalCapacity

RevisedArea

After 50Years


50 Years

RevisedArea

After 100Years



122.00 47.00 1.15 0.00 0.00 0.00 0.00121.00 34.00 0.75 0.00 0.00 0.00 0.00

120.00 26.00 0.45 0.00 0.00 0.00 0.00119.00 18.00 0.23 0.00 0.00 0.00 0.00118.50 14.00 0.15 0.00 0.00 0.00 0.00

118.25 12.00 0.12 0.00 0.00 0.00 0.00

118.00 10.00 0.09 0.00 0.00 0.00 0.00117.94 9.25 0.08 0.00 0.00 0.00 0.00117.75 8.50 0.07 0.00 0.00 0.00 0.00117.50 7.00 0.05 0.00 0.00 0.00 0.00117.00 4.00 0.02 0.00 0.00 0.00 0.00116.00 0.90 0.002 0.00 0.00 0.00 0.00115.27 0.00 0.00 0.00 0.00 0.00 0.00


All the outlets from the reservoir are fixed at an elevation abovethe New Zero Elevation estimated after considering 100 years ofsedimentation. Therefore, the life of the Kelwan reservoir has beenconsidered as 100 years.

7.6.4 Capacity 7.6.4.1 Capacities of Kelwan ReservoirSNo.


YearsAfter 100


DSL) 6.51 1.85 0.00

7.6.4.2 Storage

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Simulation analysis considering the inflow and various waterdemands to be met from Kelwan reservoir has been carried out. Based onthe simulation analysis the live storage has been provided so that thedemand of water for various requirements could be met. The dead storagehas been provided so that the functioning of the project would not beaffected even after accumulation of silt over a period of 100 years. Variousstorage details of the proposed Kelwan reservoir have been mentioned in thePara 7.6.4.1 above.

The monthly minimum storages reserved in Kelwan reservoir for meetingthe water demands towards evaporation losses, environmental and domesticneeds to achieve intended success rates are given in Table-7.39 below:

Table-7.39Monthly minimum storages reserved in Kelwan reservoir for meeting

evaporation losses, environmental and domestic needs Unit: MCM

J J Aug

Sept

ONov

DJ F March

April

May

3 3 3 3 1 11

1 9 8 5 5 5

The monthly inflow series and monthly diversion requirements consideredfor simulation analysis of Kelwan reservoir for fixing its live storage arefurnished in Appendix 5.5 in Volume – IV.


Preliminary Geotechnical Investigations were carried out at the damsite by GSI, Western Region, Jaipur at Feasibility stage of Par-Tapi-Narmada Link Project during 1993-94. As per these investigations the

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foundation rocks at the dam site are Deccan traps and it’s differentiates. Theexposed out crops are mainly consisting of horizontal to sub horizontalsequence of lava flows, which includes amygdaloidal, dense, perphyriticbasalt and flow breccias.

The report of GSI is at Appendix-4.2 and 4.4 in Volume-III. Also theperiphery of the proposed Kelwan reservoir is covered with the contours ofvalue higher than the MWL.


The simulation study carried out for Kelwan reservoir for the periodfrom 1975 to 2006 indicates that the annual average evaporation loss fromKelwan reservoir is 6.9 MCM with highest evaporation loss as 8.7 MCMduring the year 1975 and the lowest evaporation loss as 4.2 MCM duringthe year 1987. Maximum Monthly evaporation loss is in October month andleast Monthly evaporation loss is in July.




The sub-soil water table will improve due to the impoundment ofwater in the Kelwan reservoir. In addition, the regulated flows from theKelwan dam into Purna River to meet environmental needs will increase thesub soil water level in the adjoining areas even during lean season.


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The detailed geological mapping to analyze the problems of reservoirstability and reservoir competency with respect to seepage/leakage of theproposed Kelwan reservoir could not be carried out due to public hindranceduring DPR stage. However, preliminary Geotechnical investigations werecarried out at the dam site by GSI, Western Region, Jaipur at Feasibilitystage of Par-Tapi-Narmada Link Project during 1993-94. The entirereservoir area is covered by the Deccan trap and it’s differentiates. The rocktype encountered is horizontal to sub horizontal sequence of lava flows.

There is shear zones and dykes, hence adequate care should be takento control these phenomenon before impounding the reservoir.


Area of submergence of Kelwan reservoir at MWL is 1870 ha.


Area of submergence of Kelwan reservoir at FRL is 1629 ha.


The Kelwan reservoir is a part of net-work of 6 reservoirs proposedunder Par-Tapi-Narmada Link Project for diversion of surplus waters of Par,Auranga, Ambica and Purna rivers for en-route irrigation and to take-overpart command of Narmada Main Canal. The total submergence area(cultivated) under the six reservoirs is 2364 ha and the total CCA of theLink project is 232175 ha. Therefore, the Submergence Ratio works out to0.0102.


The land to be acquired is about 1629 ha (forest land: 890 ha,cultivable land: 450 ha and other lands including river portion: 289 ha) thatis coming under submergence of Kelwan reservoir.

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Due to creation of Kelwan reservoir 17 villages will be affected.These villages come under Ahwa taluka of The Dangs district of Gujarat.Total 793 households of these villages are likely to be affected.

(i) Details of Dislocation of Communication (Railways), Road(s),Right of Way, Telegraph Lines etc.) as a Result of the Project

No railway line is coming under the submergence area of Kelwanreservoir. The State Highway connecting Vyara and Ahwa is comingunder Submergence area of Kelwan dam. The power and telephone linesof about 14 km length connecting Karlipada-Khatal villages to bedislocated as a result of the project.


The Engineering Geology Division of GSI, Jaipur vide Letter No.171/G-1/EG/WR/GSI08-09 dated 9th April, 2009 (Annexure – 4.3 inVolume -II) informed that no significant minerals have been reportedfrom the Kelwan reservoir area, except construction material and a fewminor minerals like zeolites.


As already mentioned under “Chapter – 4: Surveys andInvestigations-Para 4.2.1 Archaeological Survey”, no antiquarianarchaeological remains have been noticed and none of the centrallyprotected monuments are located in the area likely to be submerged dueto construction of Kelwan dam.




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Development of Guest house, inspection bungalow and dormitory

accommodation.


7.6.10 Pisciculture

The submergence area of Kelwan reservoir is 1629 ha and there islot of scope for developing fisheries. Considering the water spread area ofKelwan reservoir and the fish production rate indicated above, expected fishproduction in Kelwan reservoir will be about 81 tonnes per year which willincrease the revenue from the project. 7.6.11 Need and Recommendation for Soil Conservation Measure

in the Catchment


Step drain


Stone masonry

Check dams

Contour bunding



Pasture development

Social forestry

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7.7. Ukai Reservoir (Existing)

As mentioned above under Para “7.0 General” neither the storage ofUkai reservoir nor the waters of Tapi River would be used under the Par-Tapi- Narmada Link Canal project. But the Ukai reservoir will be used justas a ‘Level Crossing’ for diversion of water through the Link Canal. Themonthly inflows at Ukai reservoir available from 1973 to 1998 are used forsimulation analysis carried out from 1975 to 2006. The details of storagecapacity of Ukai reservoir at important levels considered in the simulationstudy are given in Table -7.40.

Table -7.40Ukai Reservoir Storage capacities and Levels considered for simulation

Ukai Reservoir Elevation(m) Capacity (MCM)FRL 105 m 7414MDDL 82 m 684

The monthly minimum storages assumed in Ukai reservoir while carryingout simulation analysis are given in Table-7.41 below:

Table-7.41Monthly minimum storages assumed in Ukai reservoir

Unit:MCM

Jun Jul Aug Sept Oct Nov Dec Jan Feb March April

May

6729 6729

6729 6729

6729 6729 6729 6729

6729 6729 6729 6729

The result of simulation analysis is at Appendix 5.3 in Volume - IVwhich gives detailed output for the gross capacity of 7414 MCM.

7.8. Paikhed Barrage

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Paikhed barrage is proposed across river Nar about 4.6 kmdownstream of proposed Paikhed dam near village Motikosbadi inDharampur taluka of Valsad district in Gujarat State. The water releasedfrom Paikhed reservoir after power generation will be picked-up at Paikhedbarrage from where the Par – Tapi – Narmada link canal will off take.

7.9. Chasmandva Barrage

Chasmandava barrage is proposed across river Tan about 8.5 km inthe downstream of proposed Chasmandava dam near village ChandhaChikadi in Vansda taluka of Navsari district in Gujarat State. The waterreleased from Chasmandava reservoir after power generation will be picked-up at Chasmandava barrage from where a feeder pipe line will off take torelease the water in to the Par – Tapi – Narmada link canal.

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chapter- 7 reservoir -...

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