an evaluation of pakistan's flood control options

8/3/2019 An Evaluation of Pakistan's Flood Control Options

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Water &

Development

AN EVALUATION OF PAKISTANS

FLOOD CONTROL OPTIONSThis paper describes current challenges related to storage attenuation and reservoir operating rules whichhinder the inclusion of flood storage in water management processes in Pakistan. We recommend thatPakistan prioritize reforming its current flood-time operating rules according to economic tradeoffsbetween the benefits of irrigation, hydropower, and flood control. We also propose building additionalstorage as an additional and supplementary alternative, and recommend the creation of a RiverManagement Authority that takes an integrated and sustainable approach in water management.


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ContentsIntroduction ................................................................................................................................................ 3

Tarbela Reservoir........................................................................................................................................ 4

Background ............................................................................................................................................. 4

Storage Attenuation Challenges .............................................................................................................. 4

Operating Rules ...................................................................................................................................... 6

Policy Question ........................................................................................................................................... 7

Policy Alternatives ...................................................................................................................................... 7

Policy Outcomes ......................................................................................................................................... 7

1. Maintain status quo ............................................................................................................................. 7

2. Modify wet-season operation rule ....................................................................................................... 7

3. Introduce operational flexibility and adopt advanced techniques for flood-time dam operation ......... 9

4. Increase the height of the Mangla dam................................................................................................ 9

5. Build additional reservoirs .................................................................................................................. 9

6. Build a River Management Authority for integrated watermanagement ....................................... 10

Policy Evaluation Criteria ......................................................................................................................... 11

Tradeoffs of Policy Outcomes .................................................................................................................. 12

Recommendations ..................................................................................................................................... 13

Bibliography ............................................................................................................................................. 15


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Introduction

Floods are not uncommon in Pakistan, where the upper mountainous regions and foothills get heavy

rainfall during the monsoon season, adding to the base flow of snowmelt. With highly destructive floods

occurring every few years, Pakistan has intermittently experienced loss of life in large numbers and

massive damages to infrastructure and crops. Floods cause not only a one-time hit, but result in deep and

pervasive effects by disrupting productive processes and undermining a nations economic development.

Despite floods being a common and often times drastic occurrence, Pakistans perceived flood risk

appears to be surprisingly low. Policymakers appear to largely ignore the question of how to deal with

risks associated with flooding in their water management decisions. The United Nation Commission for

Human Settlements defines flood risk to consist of two components the perception of the total losses

and harm that is caused by a disaster, and the probability of occurrence of the potential disaster (Bouma et

al., 151). Perhaps the perceived magnitude of total losses and harm diminishes as time elapses and the

intensity of the event dissipates, or perhaps damages of future events are so heavily discounted that they

are valued very less in the present. The fact of the matter, however, is that the probability of potential

floods occurring remains extremely high.

A flood risk assessment of the Indus river by Khan et. al. (2011), which used maximum peak discharge

data from 1942 to 2008, ranks historical floods according to their severity, the recurrence interval, and the

probability of exceeding their last magnitude at the Tarbela dam location. The study yields that the 1992

flood, which ranked highest, has a return period of 18 years with 5% exceedence probability, the 1995

flood has a return period of 9 years with 10% exceedence probability, the 1997 flood has a return period

of 6 years with 16.6% exceedence probability, and the 2001 flood has a return period of 1 year with 94%

exceedence probability. Although larger floods are characterized by long recurrence intervals and low

probabilities of exceedence, and smaller floods occur more frequently with short return periods, the

largest floodthat of 1992which took over 1000 lives and cost approximately $825 million in damages

(Bhatti et al., 6), has a recurrence period of just 18 years. This means that Tarbela would experience aflood of this magnitude an average of three times in a persons lifetime an alarming prediction.

Moreover, the smallest of the considered floods that of 2001which still took over 200 lives and cost

$5 million in damages, is predicted to occur every year and has a 94% chance of being greater in

magnitude. The United States Army Corps of Engineers (USACE) claims that the more devastating flood

of 2010 which submerged a fifth of the country, caused close to 2000 deaths, infrastructure damages

exceeding $4 billion and wheat crop damages of over $500 million, was not unprecedented and could

happen again in our lifetime (USACE, 7). Flooding definitely is a significant and chronic threat in

Pakistan.

However, this high recurrence probability does not appear to be incorporated into Pakistans perceived

flood risk, exhibited by the lack of flood control as a priority in national policymaking. It is notadequately featured in WaterVision 2025, which has allocated $33 billion towards its focus on irrigation

water provision and hydropower generation. While additional storage has been considered with these two

objectives in mind, food control is not factored into the equation.

This paper takes the perspective of flood risk mitigation on the Indus and examines whether or not

Pakistan should build additional storage. To examine challenges with existing and future storage, this

paper highlights current stresses on the Tarbela reservoir. It also looks at operating rules necessary for


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such storage to effectively provide flood control, along with required institutional changes to set up these

operating rules.

Tarbela Reservoir

BackgroundThe Tarbela dam on the Indus River has a total storage capacity of 9.3 million acre feet (MAF), almostdoubling Indus flows in the dry season. The dam had the twofold purpose of providing replacement flows

on the eastern rivers of Pakistan which were diverted to India as part of the 1960 Indus Water Treaty, and

providing additional supplies during the low flow period to facilitate irrigated agriculture. Pakistan

envisioned that Tarbela would enable it to achieve self-sufficiency in food production, especially in wheat,

and as a by-product would generate cheap hydropower through staged development of 2100 MW capacity

(WCD, 7). Flood management was not included as an objective of the dam during its design stages, and

flood-related losses and benefits were not factored into the cost-benefit analysis (WCD, 13).

Figure 1. The Tarbela dam is located in the upstream region of the Indus(Source: USACE, 33)

Storage Attenuation ChallengesTarbela was designed to have a live storage capacity of 9.68 MAF when it started operation in 1976. By2004, this live storage had attenuated 25% to 7.67 MAF, yielding an estimated remainder life of vital

storage capacity of 50 years (Amir, 6). The water at Tarbela has high sediment content because over 90%of its catchment has young and steep geological formations that are extremely prone to erosion.Afforestation is not an option because the climate ranges from arid to hyper-arid and the soils are unstableas a result of being young and not compact (WCD, 75). Sedimentation in the reservoir has meantreduction in live storage both for agriculture (which is a priority) and for flood control (which so far hasnot been a priority). Figure 2 shows how reservoir storage capacity has attenuated over the years.


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Figure 2. Reduction in storage capacity with time(Source: Amir, Figure 1)

An unexpected additional challenge of sediment deposition is the advancement of the sediment delta,which in 2004 was 9.07 miles upstream of the dam as indicated in Figure 3. There are concerns that underearthquake loading, the sediment may liquefy and flow downstream, further encroaching storage andpossibly blocking all low-level outlets.

Figure 3. Longitudinal profile of sediments accumulated over time reducing live storage capacity(Source: WCD, Figure 3.9)


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Operating RulesThe top most priorities in determining Tarbelas operating rules are its safety, then water provision for

irrigation. Tarbela is currently operated according to the procedures presented by TAMS Consultants, Inc.

in their 1984 Project Completion Report. Current regulation is conducted by the Indus River System

Authority (IRSA).

Tarbela receives high inflows during the summer from snow melt. Figure 4 shows the average monthly

flows in the Indus, indicating heightened flows from June through September.

Figure 4. Average monthly flow (MAF) of the Indus River in MAF(Source: Amir, Figure 2)

Tarbelas operating rules specify that upto an elevation of 460m, the reservoir is filled at an average rate

of 3m/day. Beyond this level, the allowable rise is 0.3m/day. However, during low-flow periods, after

attaining the level of 466m, the allowable rise is 0.6m/day. After the daily permissible rise of 0.6m

beyond the capacity level of 466m, additional inflows are released from the spillways and outlets to

ensure dam safety. Tarbelas maximum storage height of 473m is generally reached around August 20

every year. For seasonal operation criteria, the operation of the reservoir is evaluated over 10-day periods

while considering estimated flows of the Indus at Tarbela and of the Kabul at Nowshera, provincial water

allocations at the canal head, gains and losses in the system, and other specified operational requirements.

For operational purposes, provinces prepare and submit their water requirements to IRSA, which form the

basis for actual reservoir outflows (WCD, 56). Tarbela therefore has a somewhat loose operational

framework, with reservoir releases manipulable according to provincial requests, and a lack of detailedinstructions for flood time operations.

Understandably, flood-time operations were not detailed in the dam operating rules because flood control

was not envisaged as an important function of Tarbela. Historical data however shows that Tarbela has

helped attenuate flood peaks by withholding flood water and releasing it in a slower and controlled

manner if the rise in flow occurred in the earlier part of the summer, while storage capacity was still

available. Peak flows in July 1989 and August 1997 were reduced by 26% and 43% respectively.

However, in September 1992, flows were attenuated only 2% as the reservoir was close to its maximum


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capacity at that time, resulting in highly destructive floods (Amir, 23). Since the creation of Pakistan,

floods have caused damages worth billions of dollars and have taken over 7500 lives, causing

considerable economic set-back. Perhaps flood control should be an important consideration while

determining the necessity of added storage and delineating corresponding operating rules.

Policy Question

What should Pakistan do to mitigate flood risk on the Indus? Should it prioritize building

additional storage? What should be the operating rule for current and future reservoirs?

The subsequent sections on Policy Alternatives and Outcomes will lay out the various options Pakistan

may take to mitigate flood risk on the Indus. The section on Tradeoffs will weigh the different alternatives

according to the evaluative criteria.

Policy Alternatives1. Maintain status quo2. Modify wet-season dam operation rule3. Introduce operational flexibility and adopt advanced techniques for flood-time dam operation4. Increase height of the Mangla dam5. Build additional reservoirs6. Build a River Management Authority for integrated water management

Policy Outcomes

1. Maintain status quoThis option considers action as is, with no infrastructural and institutional changes on the Indus. With

this option, flood risks will rise because of reduced flood storage due to sediment build-up in reservoirs,

increased snowmelt due to climate change, and increased exposure to population growth. Since nothing is

done to mitigate threats, future floods will likely cause damages that are similar to or greater than floods

in the past. Simulations from the flood risk assessment by Khan et al. predict that Tarbela faces flood

risks of 343,510 cfs with a 2-year return period and of 433,491 cfs with a 4-year return period. The

damages resulting from such floods will likely undermine economic and infrastructural progress. On the

irrigation and hydropower front, scarcity of water for irrigation in Sindh will continue and demand for

hydropower will increase as farmers seek to pump what limited amount is available of groundwater. The

growing population will generate pressures on food production and threaten food security.

2. Modify wet-season operation ruleThis option proposes modification of the operation rule during the wet season when the reservoir is filling

with rainwater and glacial melt, and there is a risk of floods. The proposed modification would be to

operate similarly like Tennessee Valley Authority (TVA) which takes a calculated risk that Tennessee

floods are most likely to occur during just three months of the year January through March. TVA

reserves a large fraction of its storage capacity for flood protection during these months, but not at other

times of the year. If the reservoir contents exceed the predetermined flood control line during the January


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to March period, the reservoir is drawn down as rapidly as allowed by the discharge channel (Manne, 31).

This operation rule does not impose an overestimated flood risk on the operation rule; if indeed that were

the case then the rule would be for the system to be operated for maximum flood control by maintaining

the reservoirs at minimum levels at all times of the year, just to guard against the possibility of a

catastrophic flood that has a recurrence period of hundreds of years outside the January to March interval.

Such a perverse operating rule would cause a serious loss in the reservoirs hydroe lectric and irrigation

potential.

Taking into account the random and seasonal influences that water inflows are subject to, Manne

calculates the tradeoffs between hydroelectric benefits and storage capacity reserved for flood control

during the wet period, as shown in Figure 5 below. The figure takes into account the fact that the marginal

value of electricity produced differs according to the reservoir level (the head-height effects), since more

units of electricity is produced for the a certain drawdown at higher reservoir levels than for the same

amount of drawdown at a lower reservoir level. Considering head-height effects, as shown in the figure

below, the first unit of reservoir capacity reserved for flood control purposes lowers the power benefits by

close to 2 million dollars annually, and the second unit leads to a drop of close to three million. This has

important implications for the wet-season operation rule. When the total water available is only 2 units,

then draw down one 1 unit to give up minimum hydroelectric benefits while maintaining flood storage.

When more than 2 units of water is available (more realistic for the wet-season), discharge at a rate such

that the reservoir will be filled to its 2-unit capacity at the beginning of the dry season.

A similar flexible operating rule for current and future storage would help maximize the objective

hydroelectricity and irrigation so long as the rates of filling and release are adjusted to have a full

reservoir at the end of the wet season. Meteorological forecasting has an important role in determining

such rates; this option will therefore require investment in forecasting technology.

Figure 5. Tradeoffs between hydroelectric benefits and flood-time storage.

(Source: Manne, Figure 7)


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3. Introduce operational flexibility and adopt advanced techniques for flood-

time dam operation

This option permits flexibility in operational regulations laid out by IRSA, relying upon instantaneous

information available from Pakistans newly installed telemetry to guide flood time operation decisions

(Kazi, 20). Short-term real-time reservoir flood control is different from the long-term operation rule

reservoir flood control often involves decisions that need to be made on a daily or even an hourly basis;

decisions affect only the short term period (current and immediate future); and decisions are constrained

by constantly updating forecasts of inflow. Since the 1970s, many applications for reservoir optimization

techniques such as linear, non-linear, or dynamic programming for reservoir flood control operation have

been developed. One technique particularly suitable for flood control is an optimization model using

fuzzy logic, developed by Chuntian (1999) for the flood system of the upper and middle reaches of the

Yangtze River. Conventional operational approach targets storage levels to determine outflow releases

towards achieving multiple, often competing objectives of irrigation, water supply, navigation, recreation,

water quality and salinity control. Chuntian proposes an operation alternative that maximizes outflow

smoothing by targeting not a reservoir level, but an outflow process. He does this by considering three

different sub-systems in calibrating his model the first comprises of four upper tributary reservoirs; thesecond consists of only the Three-Gorges Reservoirs; and the third comprises of four downstream

tributary reservoirs. Chuntians model allows the incorporation of the operators experience and

knowledge instead of using predetermined weights for the optimization models various objective

functions (irrigation, water supply, navigation, recreation, water quality, and salinity control), thereby

becoming an attractive contender.

This is by no means the best flood-time dam operation technology to be adopted in the Indus river system.

Indeed, the feasibility of accurate adaption of any model to the Indus river system must first be considered,

as must the availability of manpower to effectively use the technology during a time of crisis. However,

the fact remains that IRSA continues to regulate its flood-time operations using scarce operating rules

developed by TAMS in 1984; there is an urgent need for updating these rules and incorporating modern

technology.

4. Increase the height of the Mangla damThis option proposes raising the height of the Mangla dam on the Jhelum river by 30 ft which will

provide an incremental storage of 3 MAF. This will provide additional flood time storage, thereby

reducing the flood risk in the lower parts of the Indus where the Jhelum feeds into. 180 MW of additional

power may be generated if Mangla is raised. The cost of the project will be $883 million and will take 5

years. WAPDA has allocated a substantial $333 million in resettlement costs since it realized higher than

predicted benefits from Tarbela (Amir, 17).

Manglas full storage capacity has thus far filled 28 out of 34 seasons so the possibility of the added

storage provided by an increment of 30 ft has a substantial 72% reliability of flood-time use. At the end of

the wet season, the added storage will add to Manglas current hydroelectric and irrigation potential.

5. Build additional reservoirs

The fourth option would be building one or both of Kalabagh and Basha, proposed upstream of Tarbela

on the Indus. Building Kalabagh will take 8 years and $5 billion; it will provide 6.1 MAF additional


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storage and added power capacity of 3600 MW. Building Basha will take 12 years; it will provide 5.7

MAF additional storage and added power capacity of 3360 MW. The feasibility report of Basha from

August 2004 prices it at $6.46 billion due to the need to construct large roads and bridges (Amir, 10).

These costs do not take into account resettlement costs. Figure 6 shows that the benefits with respect to

irrigation and hydropower far surpass that of flood storage.

Besides directly providing additional storage, the presence of these dams will decrease the sedimentationrate at Tarbela, thereby lengthening Tarbelas life. Placed in series, these dams will provide maximum

smoothening of flood peaks on the Indus and provide increased water supply in the dry months.

As such, with sedimentation encroaching on the storage capacity of Mangla and Tarbela, raising Mangla

and building Kalabagh or Basha within the next 10 years is necessary to maintain current storage. To

ensure food and power security, the ADB study on Water Sector Strategy calls for a minimum of 18 MAF

of storage to be developed in Pakistan over the next 20 years, even under the most conservative scenarios

(Amir, 31). The USACE, which was involved in the ex-post flood assessment of the 2010 floods,

proposes that an additional 25 MAF of storage will allow sufficient management of a flood of that degree.

The construction of both Basha and Kalabagh would add a little less than 12 MAF to the combined

current live storage of Tarbela, Mangla, and Chashma.

The perceived value in building one or both of Basha and Kalabagh, or any other additional storage,

depends upon the perceived risk of recurrence of a flood of such magnitude. The final cost of the damages

of the 2010 floods are yet to be finalized, but once those are available, that can be combined with the

probability of the 2010 flood recurrence to arrive at a measure of perceived risk. If the cost of building the

dams is lower than the perceived measure of risk, then there is a strong case for the dams to be

constructed.

Figure 6. Benefits from Kalabagh and Basha

(Source: Amir, 2005)

6. Build a River Management Authority for integrated water managementThis option proposes the creation of a body that manages water resources in a holistic manner, like theMurray Darling Basin Authority (MDBA) in Australia. Such a body would provide an integrated water

management plan, incorporating benefits and tradeoffs of irrigation, hydroelectricity production, water

provision, and flood control. Assigning one body to implement and enforce the various aspects of water

management will facilitate a focused approach in attaining the different water-related objectives in the

Indus Basin. Like the MDBA, this body would gather information about the changing aspects of the Indus


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TechnicallySound

AdministrativelyFeasible

PoliticallySupportable

Basin and conduct research on relevant new technologies. It would also educate and engage the

community in managing the Basins resources.

Such a body is in complete contrast to the disjointed water management system that currently exists in

Pakistan amongst which flood control is lost as a priority. Under the WAPDA Act of 1958, WAPDAs

Water Wing has the statutory responsibility for carrying out services related to floods. However, a cabinet

resolution has instituted a separate body called the Federal Flood Commission. This is in addition to

IRSAs responsibility to oversee reservoir operating rules and interprovincial water distribution, both of

which are important flood management features. This scattered setup has led to a considerable dilution of

responsibility which results in a lack of planning and preparedness for floods.

This option proposes that WAPDAs Water Wing and IRSAs reservoir operation monitoring duties be

rolled with Federal Flood Commissions responsibilities to create the proposed River Management

Authority. IRSA, which would continue to oversee implementation of the 1991 Water Accord, would

exist under this River Management Authority. With all aspects of water management being conducted

under one umbrella, Pakistans priorities of achieving agricultural independence and industrial progress

will move forward sustainably, as it puts its best efforts in mitigating damages and deficiencies due to

floods and droughts.

Funding for the establishment of the River Management Authority would initially be provided by the

government, and a storage charge on irrigation and a water charge on hydropower may be imposed to

make the body autonomous. A flood protection charge may also be recovered from city administrations

and industrial areas which directly benefit from the integrated flood management plan (Kazi, 25).

Policy Evaluation Criteria

The criteria we will use to evaluate the above following options is indicated by the above diagram. A

favorable policy option will have three features: technically soundness its mechanics will lead to

mitigation of flood risk on the Indus; administratively feasibility it will be logistically and financially

implementable; politically supportability political supportability is essential for the realistic

implementation of any option that is technically sound and administratively feasible.


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Tradeoffs of Policy Outcomes

Proposed

PolicyTechnical Soundness Administrative Feasibility Political Supportability

Maintain

Status Quo

Low. Flood risks increase dueto reduced flood storage andincreased snowmelt. Demand

for water and hydropowerrises.

High. No further action required. Medium. Leaves currentequilibrium undisturbed; but noneamong farmers, industrialists, and

working population are satisfiedwith the current watermanagement system. Flood riskcontinues to threaten all players.

Modify

Wet-Season

Operation

Rule

High. Wet season operationflexibility and end of wetseason reservoir fillingrequirement prioritizes 1)flood risks in wet season, 2)irrigation and hydroelectricitythe rest of the year.

High. Required wet seasonoperating rule modificationsimpler than a complete overhaulof current operating rule.Implementation can be easilyguided with the proper trade-offcurves. Requires adoption ofmodern meteorological

forecasting technology.

High. Required releases in thewet season can be used forirrigation, supporting a currentpriority of the government. Wet-season releases are based ontradeoffs between hydroelectricand flood storage benefits, so neteconomic returns are maximized.

Flood-time

Operational

Flexibility

and Adoption

of Modern

Technology

Medium. Thorough researchand consultation could lead toa modern operation model thatcould effectively guide flood-time operations of existingdams, although 100% accuracyof model cannot be ascertainedprior to implementation.

Low. Research and adaptation ofmodel to the Indus River andtraining local manpower requirestime and financing. Unclearwhether WAPDA, FCC, or IRSAwould oversee transition andimplementation.

Low. A momentum fortechnological change building upin local and international advisorycommunities, however lack ofinterprovincial trust reduces thelikelihood of accepting a flood-time model-prescribed rule.

Raised

Mangla Dam

Medium. An additional 30ft onMangla increases its lifetimeand temporarily increases

flood storage, hydropower,and irrigation capacity, but therisk of larger floods on theIndus remains.

High. The government hasallocated resources for this optionand has prioritized higher-than-

prior resettlement costs whichwill facilitate implementation.

High. This option offers a quickway of buying additional storagewhile other options are still in

consideration.

Additional

Reservoirs

High. Basha and Kalabaghwill raise storage capacity,increase outflow smoothing,and increase Tarbelas

lifetime. Both dams yield highbenefits for irrigation andhydropower.

Medium. Kalabagh is favorablebut Basha is more challengingbecause of its terrain. Findingfinancing is a challenge, unlikeduring for Tarbela and Manglawhere financing was supplied bycompensation through the IndusWater Treaty.

Medium. Project planning iscompleted for Kalabagh. Projecthas central governments support,but interprovincial tensions andlack of finance have blockedproject commencement. Sindhfears that Punjab will retain itsrightful share of water.

RiverManagement

Authority

High. An integrated body canlead to a holistic approach inwater management, as shownby the MDBA. Irrigation,hydroelectricity, waterprovision, and flood controlwill be appropriatelyconsidered in determiningstorage and water distribution.

Low. Rolling together WAPDAsWater Wing, IRSAs operational

rules responsibility, and FCC intoone body will likely be lengthyand administratively demanding.Initial financing will be achallenge, although it may bepossible to sustain it throughtariffs in the long-run.

Low. Sindh and Punjabparticularly will resist transferringtheir barrages to a federalauthority.


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Recommendations

As per the outcomes discussion and tradeoff analysis conducted in previous sections, we recommend that

Pakistan consider the top four alternatives in the given order in its aim to mitigate flood risks while

upholding the objectives of irrigation and hydroelectricity production. All four options respond to the

currently faced storage attenuation and operating rule challenges described earlier in the paper.

1. Modify wet-season dam operation rule2. Increase height of Mangla dam3. Build additional reservoirs4. Build a River Management Authority for integrated water management

Modifying wet-season dam operating rules is the most favorable of the considered options as it increases

the effectiveness ofexisting storage. Since it does not involve adding any infrastructure to the system and

concentrates on reforming operation guidelines during the high flood-risk season, it constitutes of a

minimal intervention which renders it the simplest to administratively implement and the most politically

supportable. The requirement to drawdown reservoir levels during the flood-risk season is instituted inparallel with the requirement to fill the reservoir to its maximum at the end of the season, necessitating

investments in modern meteorological forecasting technology which will guide reservoir release and

filling rates. Such technology has been adopted at other major reservoirs like the Three Gorges and in the

Tennessee Valley. Expenses are projected to be considerably lower compared to the other options

requiring additional infrastructure. Having such technology in place will allow for stringent reservoir

drawdown to be called for only when flood-forecasts are high, thus reducing the likelihood of

unnecessarily foregoing future hydroelectricity and irrigation benefits. Also, drawdown levels will be

guided by carefully determined tradeoff curves between flood storage (which depends on the degree of

flood-risk), hydroelectric benefits, and irrigation benefits, so that the system as a whole reaches an

optimal outcome. For example, foregoing a certain amount for future irrigation might generate a net

benefit if the corresponding storage space in the reservoir is able to smoothen a critical flood peak that

might otherwise cause heavy damages to the agricultural sector itself. This rationale gains this option

substantial political favor, provided that the tradeoff curves have been impartially and transparently

prepared, and all involved sectors are sufficiently informed about them.

We recommend adding storage to the system as an additional and supplementary alternative. Although

raising the height of Mangla will temporarily buy storage, the fact remains that Mangla is much smaller

than Tarbela. Raising the height of Mangla will not mitigate the sedimentation problems that are rapidly

decreasing the storage of itself or Tarbela. The government has allocated the resources and has a

construction plan ready for Mangla, but this can only be a temporary solution, and one that specifically

requires flood time operating considerations to be incorporated into its operating rule. Otherwise, as per

the current protocol, the added storage space will simply be filled to the top at every wet-season, leaving

no flood storage space, and rendering any subsequent floods to be even more devastating. Thus our first

recommendation is imperative for this second recommendation to be effective in flood control.

Building Basha and Kalabagh are technically more attractive, since the storage they provide are

considerably larger, making it politically easier to allocate the required amount for flood control. They are

also part of Pakistans WaterVision 2025 plan. They will offer more capacity for flood control, and will

also considerably slow down the sedimentation at Tarbela, adding a projected 30 years to its current 50


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year lifetime. However, financing is a serious issue with these bigger projects, especially with the World

Bank unlikely to provide support. Perhaps financing might be acquired through the Asian Development

Bank which receives the project more favorably.

We deem that in the long run, the presence of an integrated River Management Authority is essential for

water management endeavors in the Indus Basin to take on a holistic approach. This will reduce barriers

that arise due to inter-agency and inter-provincial differences, increase the effectiveness of water

management processes in the system, and ensure that flood control is regarded as a vital part of

sustainable water management in a high flood risk country such as Pakistan.

Word Count: 4275


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an evaluation of pakistan's flood control options

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