Application of WEAP Simulation Model to Hengshui City Water Planning

Transactions of Tianjin UniversityISSN1006-4982pp142-14Vol 13 No. 2Apr 20OApplication of WEAP Simulation Model to Hengshui City Water PlanningOJEKUNLE Z0,丌 HAO Lin(赵林), LI Manzhou(李满洲)2, YANG Zhen(杨真), TAN Xin(谭欣)(1. School of Environmental Science and Engineering, Tianjin University, Tianjin 300072,China2. Institute of Geological Environment Survey of Henan Province, Zhengzhou 450006, China)Abstract: Like many river basins in China, water resources in the Fudong Pai River are almost fully allo-cated. This paper seeks to assess and evaluate water resource problems using water evaluation andplanning(WEAP)model via its application to Hengshui Basin of Fudong Pai River. This model allowsthe simulation and analysis of various water allocation scenarios and, above all, scenarios of users'behavior. Water demand management is one of the options discussed in detail. Simulations are proposedfor diverse climatic situations from dry years to normal years and results are discussed. Within the limitsof data availability, it appears that most water users are not able to meet all their requirements from theriver, and that even the ecological reserve will not be fully met during certain years. But the adoption ofwater demand management procedures offers opportunities for remedying this situation during normalhydrological years. However, it appears that demand management alone will not suffice during dryyears.Nevertheless, the ease of use of the model and its user-friendly interfaces make it particularlyuseful for discussions and dialogue on water resources management among stakeholdersKeywords: water allocation; WEAP model; water demand management river basin management; waterresources management; water demand coverage; unmet water demand; Fudong Pai RiverThe on-going Hengshui water"One River three sysWater resources have been developed in hengshui btemsis expected to bring about fundamental changes in the sin. Water demand management, especially in the agiway in which water is used and shared among different use- tural sector, the biggest water user, is one of the possiblers.A major aim is to ensure a better balance among effi- solutions being considered by the hengshui City water depciency,sustainability and equity needs in water allocations. artment. In order to quickly assess alternative water allocaWater must be guaranteed for all, especially to meet the ba- tion scenarios at basin level, technicians and policy makerssic human needs of poor people in rural areas who have will need practical and user-friendly toolsbeen disadvantaged for so long. Furthermore, water shouldThis study sets out to test the usefulness of the waterbe allocated not only to meet the increasing demand from evaluation and planning(WEAP)model in this regardagriculture, industry and other productive sectors but must particularly in assessing scenarios of water demand managealso satisfy the requirements of aquatic ecosystems and the ment, by applying it to Hengshui- basin of Fudong Pai Rivecological reserve. Finally, responsibility for decision-mak-ering in respect of water allocations will have to be decentralized to the level of the future Hengshui water management1 General presentation of the WEAPadministration. a system of authorizations for water abstracmodeltions is foreseen, with compulsory permission licensing esThe Stockholm Environment Institute(Sel)lIi depecially when the basin water is overstressedoveced the WEAP model The model operates at a montSuch is the case of Fudong Pai River basin and its step on the basic principle of water balance accounting. Thegroundwater resource exploitation, which flows across the user represents the system in terms of its various sources ofcity as shown in1gsupply (e. g. rivers, groundwater, and reservoirs ), witAccepted date: 2006-09-11OJEKUNLE ZO, bom in 1975, male, doctorate studentE-mail:oojekunle@yahoo.comOJEKUNLE ZO et al: Application of WEAP Simulation Model to Hengshui City Water PlanningRiverCity: GroundwaterRural UsageIrrigation catchment (1)HS City-Water-(1)Ei Dong: Pai River..A中 s, WWTP Adder-rigation GroundwaterMENe对 p River-R9s9ror-Nifi maocYed fe udaWei Qian Chu Linking Yellow RiverFig 1 Location of Hengshui lake sub-basin in relation to Fudong Pai river basin and major county boundariesin solidline)in Hengshui municipality, and the main rivers and the quaternary basins, which are the basic hydrologicalunits considered in this paperdrawals, water demands, and ecosystem requirementsrequirements or local constraints and conditionsWEAP applplications generally involve the followingThe present application of the WEAP model forms partsteps[1jof ongoing research at the Intemational Water Managementboundary, system components and configuration, spatial Institute(IWMI) to develop lest and promote management(1)Problem definitions including time framepractices and decision-support tools for effective manage(2)Establishing the current accounts, which provides ment of waler and land resourcesa snapshot of actual water demand, resources and suppliesWEAP has been described as being comprehensivefor the systemstraight forward and easy-to-use, and attempts to assist(3)Building scenarios on different sets of future trends rather than substitute for the skilled plaangerbased on policies, technologicaldevelopment, and other 2 Introduction to Hengshui lake sub-basinfactors that affect demand, supply and hydrology(4)Evaluating the scenarios with regard to criteriaHengshui lake is an important tributary of Fudong paisuch as adequacy of water resources, costs, benefits, and River, contributing useful inflows of fresh water during crit-environmental impactsical periods; Fudong pai river itself is one of the referenceThe scenarios can address a broad range of what if" (or benchmark basins where the Hengshui municipality foquestions, such as: What if population growth and econom- cuses much of its research effort in hebei Province, Chinaie development patterns change? What if ecosystem require- Fudong Pai River is chosen to pilot-test this application ofments are tightened What if irrigation techniques and crop WEAP because project on water decision system has alreadypattems are altered? What if various demand management been extensively carried out in this basin and it is a relastrategies are implemented?ly simple basin/ lake with no large dam or some inter-bAn intuitive graphical interface provides a simple yet sin transferspowerful means for constructing, viewing and modifying theHengshui sub-basin has a total area of 8815 kmt withsystem and its data. The main functions--loading data, a rather rhombus shape with a sea level of 12. 6 to 30.0 mcalculating and reviewing resultsare handled through an The topography gradient in the west of Fuyang River andinteractive screen structure. WEAP also has the flexibility that in the east of the Fu river ranges from 1: 4 000-to accommodate the evolving needs of the user, e.g. avail- 1: 6000 and 1: 6 000-1: 8 000 respectively. The vegetaability of better information, changes in policy, planning tion can be divided into three categories: grassland, forest143THCnWIGTransactions of Tianyin University VoL. 13 No. 2 2007and savanna covering the southern part of the area. Thelemand could amount to a significant quantity. Howeversin is densely populated(469 inhabitants/km )with some neglecting this demand is a conservative assumption becausesmall towns and a very crowded rural population scattering any difficulty in satisfying major water users will only be ex-widely. The city annual CDP stands at 2. 663 million yuan acerbated by the addition of minor users, driving home theand its plantation agricultural land is estimated as 582 598 need for even greater efforts on the demand managementHa. The main job opportunities are in agriculture and for- side For each major user, the activity level, the annualestrywater demand (net values after accounting for lossesA maior feature of this basin is that its mean annual monthly variation as well as a return flow( generally 5% forrainfall( MAR)is relatively low(185 million m/year), irrigation schemes in accordance with Hengshui field surcompared with other catchment basins. The available water vey) are introduced(see Tabs. I and 2 ). Growth ratesresources for the basin is estimated to be 82 million m tween 1993 and 2030 were computed as follows: domestic(Field survey 2003 )with 47% from groundwater, 25 1 2%-2.0% and irrigation 1. 2%from surface water and the rest from water import3.2 Hydrol3 Setting WEAP application for Fudong of nodes connected by river reaches, which have to bePai Riverdrawn A ritde has been introduced at the mouth ofAs mentioned earlier, data collection is a critical slep each quaternary basin as well as where 7 tributaries meetingin setting up WEAP. The characterization of the water sys- the Hengshui lake, Naturalized monthly flows at each nodetem involves collecting and entering into WEAP the follow- were provided in an electronic format directly utilizableing data: water uses( demand sites), Hengshui reservoirs WEAP, based on a study carried out on the hydrology of(location, capacity and operation rules), and flow gauging Hengshui river basin. With 2 gauging stations on the Fudstation( flow requirement and ecological reserve ), river ong Pai River, the hydrology is well described. One musthead flows See tabs. 1 and 2note that the adjoining Rong Wangdi, Ji Nanchu, Ji NichuJi Maochu, Ji Zaochu, and Yao He gudao sub-basins haveTab 1 Various past data used in calculating the waterbeen taken into account in WEAP as a flow directly entersresources demand for the period 1993-2003Hengshui lake system accounting for 14.4, 20, 14, 17.7Demand site parameters8 and 12. 3 million m' respectively, with surface and waterHengshui City water uses Hengshui imigationimport accounting for the annual average 60 and 101. 1 milAnnual activity level4.13population 459 500 halion respectivelyAnnual water ral23.9/prn3115/hThe role of groundwater is important since 50% of cityte %owater resource depends on ltJan Feb Mar AlJun Jul Aug Sep Oct Now decIn WEAP, it is possible to quickly create different cliRiver headfiow/106514%126683matic situations ranging from very wet to very dry Based onIrrigation variation%00 3 1010 20 27500the analysis of observation of many years(1965-2003)the flow during the year 1997 was found to be the closest toTab 2 Comparing actual and WEAP applicationthe mean annual flow in the middle of the basin, and wasmodeling software for validitythus chosen as the year of referenceAnnual averTota199320033.3 Ecological reserveWEAP computation 1 520 9715816730687402The hengshui administration accords an absolute priActual observation152126600016733926000ority to meeting basic human needs and ecological reserveDifferences2944183238598This is referred to as In-stream Flow Requirement(IFR)Note: The differences are a result of water losses due to evaporation not incor- situated at Hengshui lake (upstream of Hengshui town)porated in the actual computationsThe IFRs have been defined for dry years( drought flow)and for normal or wet years( maintenance flow ). It is im-3. 1 Demand site analysisportant to note that there are two components in the reserveOnly major water users were described (over 100 irri- low flow and floods. Floods and summer flow events aregation schemes, 12 towns, 1l industries and one main res- fundamentally visible, as floods are essential to the ecologiervoir). Minor user demand was neglected due to inade- cal functioning of the river for a variety of reasons and mainquate information, though when lumped together, their total taining the water status in the basin. Consequently theyOJEKUNLE Z O et al: Application of WEAP Simulation Model to Hengshui City Water Planningaye been considered inthe determination of ifrscity as a whole3.4 Water demand management optionsWater demand management options can be included inTab 3 Annual percentage increase in city and overallWEAP either at specific sites( for example, by studying thetotal water demands as a result of higher population growthpossibilities for saving water using disaggregate demand.-(1. 12% to 2.0%)for the reference period (1993 to 2030)washing machine) or globally. This paper chose to considerScenariodemand/the effect of overall efforts of all users, especially irrigationefficiency and population growth. The efficiency of water City water use reference225699027.07124508037.32use by agriculture in Hengshui is estimated by WeAP to bePopulation growth 2868 060170976013%(WEAP Computation). Even as a local figure it sug- All demand Reference 7 188 670 8.50 3 550 60015.76gests room for improvementPopulation growth 7 799 740 4110 190These targets could be achieved through a variety ofmeans such as licensing for groundwater exploitation, waterThese shortages sometimes account for 37. 32 of thepricing, public participation, fines and surcharges during city water demand and 15.76% of the total overall city decrisis periods and water importsmand in some cases(e. g. the northem part of the city4 Results and discussionBut, in general, they are of limited magnitudes(e.g. 1%in the case of irrigation schemes4.1 First simulationsThe simulation with WEAP suggests that the requireWater users experience periods of unmet demand- ments for the months of June to November will be difficult toeven during normal years, it appears that some counties(7 be met in years(e. g 2009, 2014 and 2025 to 2030)thatout of 12)have already experienced unmet demands as have hydrographs similar to that of 1997, when precipitationshown in fig 2will occur late in the season, the peak flows will appear inMay or June with no flows in December and January and the→ Domesticsustainable groundwater exploitation level will be negativThe ecological reserve will therefore not be met during thosemonths unless water demand managerment is promoted evenat a limited level, increasing water reservoir to 300%andnecessarily importing 1.3 billion m' of water resources an04. 2 Water demand management scenariosThe simulation results shown in fig. 2 demonstrate thatFig 2 Average monthly unmet water demand calin nomal years and without irrigation efficiency efforts, theculated by the modelrequirements of water demand of at least 9 counties wouldgo unmet. Moreover, for certain users, even extreme waterUnmet demand is defined as the quantity of water that demand management efforts (i.e.80%)would not becannot be physically delivered from the river during a part enough. This is possibly a consequence of their position inof the year, especially during the farming season. This situ- the basin, and merits further investigation. On the otheration is likely to deteriorate in the future due to the progres- hand, at certain other locations, limited efforts appear to besion of water demand and especially if no measures are tak- sufficient to meet local requirementsen to address themDemand management can help achieve reserve requireThis result merits careful analysis as it does consider a ments-increased reservoir capacity, supplemented groundnegative balance for the Hengshui basin, suggesting the water resource, water recycle and reuse(see Tabs. 4 andpossibility of future problems especially in the face of high 5). While Fig. 3 shows that with irrigation efficiency andpopulation growth, moreover, this scenario increases the increasing Hengshui reservoir demand management effortswater unmet demand by 10% over the computed reference some inflow water demands might not be fully met,evenyear(see Tab. 3). It has been observed that many counties during normal hydrological years. However, the WEAPhave devised their own strategies to cope with shortages, simulations show that with at least 50% and 15%watere.g. using well or developing their own storage systems, management as regards to high population and increased wawhich have detrimental effect on the ecological setting of the ter reservoir capacity and also water demand management145THCnWIGTransactions of Tianyin University Vol 13 No. 2 2007effort, the reserve targets could all be achieved (see Tab. Hengshui water planning used WEAP as a research tool to5). Demand management alone will not suffice during dry simulate and analyze water allocation scenarios in river ba-years. In the case of dry years, the simulation results show sins, taking into account variations in abstractions, de-that more water importation is necessary especially from mands and ecosystem requirementsYellow River, 2 counties would, however, experieFor example, the assumption that groundwater doeslems instead of 7 during normal years. This suggests that play a major role(as a source of water for users and also asdemand management alone would not be enough and that, a source of water for the base flow in the river) and cow/dprobably, other measures( such as compulsory licensing or influence the results of the study. It was also observed thatfurther development of water resources, using washing main the absence of large storage dams in the basin, water uschine and disaggregating demand and the compulsory water ers and water management were dependent on river flowsimportation)would also have to be envisaged)and levels. Some counties seem to have developed their ownstrategies to confront such circumstances, for example,farmers dig well in the river, sink boreholes or develop theirTab 4 Supply quantities for the proposed reservoirown storage facilitiesInitial storage/m Final storage/84650000Careful verification of declarations made by countiesA46500000Volume/mA46500000646500000946500000and users in this regard is indicated Incorporating waterCmportation use and carrying out simulations to assess the10.070.10.0elevation/mimpact of the behavior of different counties and users wouldopBufferprovide further insights and guidance regardinsTop of buffer Top of inactivement of water resources in Fudong Pai river s the manage-40000033000000320000m30.78n order to alleviate water resource problems, thereNet evaporation 32 mm per month Groundwater269000000need to further disaggregate water demand, improve irrigaTab. 5 Percentage coverage giving watertion efficiency, create natural catchment areathe model to include the new Fuyang river, implement wareuse scenaroter pricing for water demand, increase reservoir capacity,Reference year High population Reservoir addedHS city. 44.8and build waste water treatment plant WWTP). These po558tential useful recommendations will improve and alleviateRural98.190.6poor water conditions in Hengshui municipalityReterences10[1 SEI. WEAP( Water Evaluation and Planning): User Guidefor Weap2i stockholm Environment Institute, BoUsa.Availablefromwww.seiborg/wcap/,2001[2] Yates D, Purkey D, Sieber J et al. a physically basedwater resource-planning model of the Sacramento BasirCalifomia USA[J]. ASCE Joumal of Water ReReferencePlanning and Management, 2005Increased reservior capacit[3 Yates D, Purkey D, Sieber J et al. WEAP21--a demand, priority, and preference-driven water planning modfig, 3 availability of water to irrigation de-el(Part 2): Aiding freshwater ecosystem service evaluationIJ. Water International, 2005, 30: 501-512mand site as a result of increased reser-voir capacity calculated by the model[4 1.laurer E P, Wood A W, Adan J c et al. A long-termhydrologically-based datsuracestates for the conterminous united states [J]. Climate5 Conclusions2002,15:3237—32511 Yates D, Purkey D, Sieber J et al. WEAP21- A de-This study represents the first attempt lo apply and testmand, priority, and preference-driven waler planning modthe WEaP model as a means of addressing water allocationel( Part 1): Model characteristics J]. Water Internation-al,2005,30:487—500.questions in a water-stressed river basin in Hengshui cityAdditional water needs in such a basin can be met through[6] Levite Herve, Sally HiImy, Cour Julien. Testing water demand management scenarios in a water-stressed basin increation of storage facilities, gains in water productivity, bySouth Africa: Application of the WEAP modell j]. Physireallocation or by augmentation from imported sourceand Chemistry of the Earth, 2003, 28: 779--786一146一HtN I D