hydrosurvey rev

7/29/2019 Hydrosurvey Rev

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GENYEM HPP

Method StatementHIDROLOGY MEASUREMENT AND ANALYSIS

FOR DETAIL DESIGN GENYEM HPP - PAPUA

1. Prefase

Genyem HPP is located in the down stream reach of the Sermo river, Papua.

Based on FS and RFP in Bid Doc this project will construct a “run-off river” type

(ROR), with average discharge at diversion intake 13 m3 /sec and reliability

discharge will be 97% or 12 m3

/sec.

Allthough there are some avalaible secondary data and FS report of Genyem

HPP, it is necessary to have lattest Hydrology data to convince the parameters

that will used for detailed design by perform the Hydrology measurement survey

and analisys.

The survey purpose are :

1.

To obtain river discharge of Sermo River and Rewo River2. To obtain water level recording of Sermo River and Rewo River

3. To obtain sedimentation (suspended and bed load) of Sermo River and RewoRiver

4. To obtain water physical & chemistry quality of Sermo River and Rewo River

The Analysis purpose are :

1. Secondary data collecting and Study , which gotten from some sources

such as BMG, Water Management , Public Work, PLN Wilayah etc.

2. Data analisys process which will review from previous FS to compile with

site survey.

3. Calculate the design discharge and water availability at proposed weir site

using some formula & standard.

PT. WASKITA KARYA – GXED/TKL halaman 1



W1 W2 W3 W 4 W 1 W 2 W 3 W 4 W 1 W2 W 3 W 4

1. Preparation

2. Mobilization

3. Reconnaisance

4. Staffgauge Installment

5.

Sermo river Flow Measurement,

Cross Section and Sampling atIntake area

6.

Sermo river Flow Measurement,

Cross Section and Sampling at

Power-house area

7.Rewo river Flow Measurement,

Cross Section and Sampling

8. Laboratory Test

9. Analysis and Reporting

No. DescriptionJun-09 Jul-09 Augst

GENYEM HPP

4. Optimizing studi of turbine operation based on its analisys & calculation

compile with wet & dry season consideration.

2. The Team

To conduct the Hydrology measurement and analisys, the consultant need to

perform team for implementation site and analisys office as well .

The minimum team configuration will be as follow :

a. Hidrologist Specialist

b. Water Management Engineer

c. Hydraulic Engineer

d. Computer Engineer

e. Hydrologist Assistant

f. Water Management Assistant

g. Surveyors

3. Implementation Schedule




GENYEM HPP

4. Scope of Works

4.1. Installment & Read of staff-gauge/Peilschaal

a. Staff gauge, a measuring scale which takes in the lowest and highest

probable water level in the cross section, should be installed at the

proposed location of intake and power house.

b. Zero on the staff gauge is to be situated at the lowest point of the

scale so that all readings are positive.

c. Zero on the scale must be leveled to the nearest fixed datum point

(bench mark).

d. Regular observation of the water levels are made at every two hours

daily.

e. The daily weather information during water level observation will be

recorded in the report.

River Cross Section

a. The river cross section measurement will be conducted at proposed

intake and tail race of power house location.

b. Cross section should be made 90º against river flow, cross section will

be measured using Theodolit equipment.

c. The interval of cross section measurement not more than 2 m wide

(Sermo River and Rewo River)

Measuring the River Velocity

a. River velocity should be measured using callibratted current meter .




GENYEM HPP

b. The location of velocity measurement will be at cross section around

proposed intake and tail race of power house location .

c. Measuring should be at Low , Medium and High water Level.

d. Velocity will be measured at every two hours in a day (10 times

totally), for Sermo River and Rewo River.

4.4 Sediment Sampling

4.4.1 Suspended Load Sampling

a. Suspended load is the transport of bed particles which are in

suspension when the gravity force is counterbalanced by upward

forces due to the turbulence of the flowing water. This will sampled at

Intake location.

b. Taking of sample and Velocity measurement will be conducted at the

same time and same frequent.

c. Before fill in the sample the surveyor should measure the water

temperature.

d. Concentration of sediment in each water sample will be conducted in

laboratory.

e. For each bottle sampler the following information should be recorded :

• Sample Number

• Location

• Time & Day

• Staff gauge data

• Distance from river edge• Water temperature




GENYEM HPP

4.4.2. Bed Load Sampling

a. Bed load is the transport of sediment particles by sliding, rolling or

jumping over and near the riverbed. Bed load sampling will be carried

out at intake and Power house location using the bed load

sampler/Grabber.

b. Bed load sample will be carried out 4 times at 3 point in a cross

section. Water temperature should be measured during the sampling

and should be recorded in the sample container.

c. Laboratory test will consist of grain size and specific gravity

d. For each container, the following such information should be

recorded:

i. Sample Numberii. Location

iii. Time & Dayiv. Staff gauge datav. Distance from river edgevi. Water temperature




GENYEM HPP

5. Water Quality

a. Sample of water quality will be taken at proposed intake and tail race

of power house location.

b. Water sample will be tested in laboratory to have water quality

characteristics such as :Fisically charateristic : PH, Conductivity, turbidity, total hardness ,

etc.Chemical content : Sulfat, nitrat, chloride, calcium, mercury,

etc.

6. Water discharge curve

Water discharge curve analysis will be carried out at proposed intake and tailrace of power house location. The analysis consist of :

a. To perform river cross section.b. To calculate discharge at both sites by area velocity method.c. To perform the relation between stage and discharge (water discharge

curve) using regression analysis.

7. Water availabi lity analys is

Water availability analysis will be carried out on monthly bases. The analysisconsist of :




GENYEM HPP

a. To perform rainfall-runoff analysis using mathematic model NRECA. Thismodel will transform monthly rainfall to monthly flow. The modelparameters will be calibrated using recorded flow.

b. Based on generated monthly flow from NRECA, flow duration curve will be

established. To estimate the frequency of low flow discharge at proposed

intake, the flow duration curve will be examined on the bases of monthlymean discharge.

8. Flood analysis

Flood analysis will be carried out based on availability data. No historical flooddata record available in the project. Fortunately long record of maximumannually daily rainfall data available at 4 rainfall stations namely Nimbokrang,Genyem, Besum and Sawoy, even though all rainfall stations beyond thecatchment area boundary of proposed Genyem HPP.

Based on the data availability above, the flood analysis will be carried out usingrainfall-runoff model such as synthetic unit hydrograph Synder-SCS andNakayasu.

The flood analysis consist of :a. To perform frequency analysis of maximum annually daily rainfall at 4

stations, with return period of 10, 25, 50,100 and 500 year.b. To perform areal design rainfall for Genyem HPP catchment area.c. To transform design rainfall to design flood hydrograph using synthetic

unit hydrograph Snyder-SCS and Nakayasu.

9. Survey Equipment

In carry out field Hydrology Measurement the consultant need to provide survey

equipment for implementation .

The minimum survey equipment will be as follow :

a. Current meterb. Grabber

c. Dept Integrating water sampled. Peilschaal/staff gauge

e. Water thermometerf. Theodolitg. GPSh. Camerai. Botle sample




GENYEM HPP

10. Analysis and Reporting

The engineer team will perform analysis the possibility of turbine operational

during the life time of Power plant interconnected to system in the future.

Analysis it self will need several data’s and professional parameters such as:

1. Long life discharge (30 – 50 years) of Sermo river from existing

related government institutional such as PU Pengairan, BMG , Balai

Besar Sungai , PLN wilayah, PLN Pikitring, etc. Particularly to

analyze the power plant operation in extreme hydrology condition

such as Wet or Dry long season.

2. Design flood discharge of Sermo river with return period 500 years.

3. Perform a “rule curve ” data to analize power plant operation in

various hydrology condition (wet, normal and dry). For each

condition will take 2 “rule curve ” with percentage of probability.4. Perform “ stream – flow forecsting “ (monthly basis) for data

proccesing that will take the suitable rule curve to be choosen for

optimizing.

5. Perform Hidraulic data which will use for Genyem power plant

detailed design analysis such as : Water hammer, Water presure in

water way, Power generation posibility, Energy optimizing in

related Lay out/Hydraulic structure .

6. Perform Operation manual to operate the power plant in aspect of

hydrology and hydraulic.

The hydrology survey Report & result from field and laboratory will be prepared

and presented as a report which has contents includes:

1. Discharge measurement report, consist of time of measurement, water level,

cross section area, water velocity and river discharge.

2. Water level measurement report, consist of water level record and weather

condition.

3. Suspended sediment sampling report, consist of water level, sedimentconcentration, river discharge and rate of sedimentation.

4. Bed load material sampling report, consist of specific gravity, sieve analysis

and grain size.

5. Water sampling report, consist of physics and chemistry parameter (organic

chemistry and radioactivity).


hydrosurvey rev

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