A Dissipative Hydrological Model for Oasis in Arid Area TANG, Qiuhong Oki/Kanae Lab. The University of Tokyo IHWR, Tsinghua Univ

About the model Water & Salt Balance Model World Bank projects in Tarimu River I developed the model by making the water cycle relations more reasonable, adding the soil water module, putting it into action. Background

About the model The key of sustainable development of arid area is water resources. A model for arid area will do favor for water resources management. There are lots of famous conceptual hydrological model such as Standford, Sacramento, Tank… These models can work well at humid area. A model for arid area

Water cycle in river basin A model focus on dissipative flow

River basin in arid area P<<EP>E RFA (Runoff flow area) DFA (Dissipative flow area ) a mountainous areaplain area The region, a lake or a stream ， a waterway ， a reservoir supplies to water, or a lake or a stream ， a waterway ， a reservoir receives runoff which originates from precipitation. watershed

Difference between dissipative flow model and runoff model Research area is arid area. Usually, a dissipative flow model need not a module to simulate runoff, but it need a dissipative flow module. Human activities( irrigation, pumping groundwater,.. ) must be considered. Evaporation should been calculated more precisely. (soil water, crop, irrigation, management level…)

Profile of water cycle in DFA channel water River seepage Groundwater exchange drainage Agriculture area Non-agriculture area Irrigated cropNon-Irrigated cropLowlandNaked landRiverReservoir River is the main water supplier. The transfer between atmospheric moisture, surface water, soil water and groundwater is very complex, and the dissipative flow is distinguished. Precipitation Water surface

Water decentralization in DFA drainage Reservoir channel Irrigated crop Non-Irrigated crop Groundwater flow Spring/well channel River inflow outflow seepage

Framework of the model Groundwater exchange Agriculture area Non-agriculture area IrrigatedNon-Irrigated Lowland Naked River Reservoir Water surface Soil Industry GW Reservoir River SpringWell Drainage Channel water River seepage Industry Naked land Non-IrrigatedLowlandIrrigated

Framework of the model Atmosphere Soil water Groundwater

Framework of the model 12 3

1. Agriculture area module I,P: irrigation water, precipitation EU,EM: evaporation of Up-Soil layer and Down-Soil layer EG:groundwater supplying soil water FWM:seepage water to Down-Soil layer FGW:seepage water to groundwater IGW:groundwater from river, reservoir, … IIG:groundwater exchange between Agriculture area and Non-agriculture area DR: drainage E =EU+EM Channel Seepage E Note: All these parameters use water depth, unit: millimeter/ month. Up-Soil Down-Soil Groundwater

Ea: Evaporation Ability Let evaporation ability be Ea, potential evaporation be Ep, crop coefficient be Kc, then: Ea=Ep*Kc Ep(FAO, Penman-Monteith ) Kc

E=EU+EM

EG:groundwater to Down-Soil layer Ea E 0 : Water surface evaporation Phreatic water evaporation:

DR:drainage We assume it is Dupuit flow, and use the Dupuit equation : Drain Field

2. Non-agriculture area module

Non-agriculture area Evaporation E0E0

3. Groundwater Exchange System Type1 Type … Type3Type2 Also we assume it is Dupuit flow, and use the Dupuit equation to estimate groundwater exchange

Applications of Model Based on the research on the pilot area of Akesu River basin oasis in northwest China, I will introduce the development and application of the dissipative hydrological model for arid oasis. Both the evaporation in agriculture area and in non-agriculture area as well as groundwater exchange from Jan 1999 to Dec 2002 in Akesu River basin oasis are calculated by the model.

Research area Tarimu River Akesu River

Area: 12,000km 2 Precipitation: 30-90mm/year Water-surface evaporation : mm/year Sketch of Research Area Shaliguilanke Xiehela Alaer

Sketch of riverway Legend Station Reservoir Riverway

Comparison of the simulated and recorded hydrograph at Xidaqiao Station Comparison of the simulated and recorded hydrograph at Yimapaxia Station Comparison of the simulated and recorded hydrograph at Alaer Station simulated observed runoff simulated observed runoff simulated observed runoff

Water table Comparison of the simulated and observed water table at Unit 3 Comparison of the simulated and observed water table at Unit 4 simulated observed simulated observed

Result: main water cycle

Result

Summary Out of the results in Akesu river basin, we can draw conclusion that the model works well in Akesu river basin which is a representative plain oasis in arid area, and more applications of the model in northwest China may be possible.

Further Research The model, based on a typical DFA, focus on dissipative flow, runoff flow is simplified. How to establish a model which focus on both dissipative flow and runoff flow? The groundwater exchange system is complex, and it is hard to distribute groundwater to land types. It is hard to ascertain some parameters, such as drainage coefficient and channel coefficient. A model system is requiredA model system is required. My colleagues are employing the model to other basin (Hetianhe river, Weiganhe river, Kai-konghe river )in Xinjiang. I will develop the model according to the applications.

Unit 1 next ： unit2

Unit 2 next ： unit3

Unit 3

Unit 4

Unit 5

Unit 6

Programming language: Delphi 5.0 Database: MS SQL Server 2000 Operating system: Windows 2000 / Windows XP