Simulation Research Of Groundwater In Karst Valley Based On BASINS/HSPF Model

The hydrology modeling technology has become a hot topic of present hydro-geological research,it is an effective means to study complex water moving characteristics.This thesis is supported by programs-"The evolution mechanism and influencing factors of water resources in southwest karst area(2008CB417208)" and "The formation,distribution and the water cycle rule of karst sub-stream in Chongqing(CSTC2007BC7001)",we carry out study in QingMuguan sub-stream system in Chongqing,try to simulate the rainfall and runoff behavior with BASINS/HSPF model,which developed by the U.S.Environmental Protection Agency. Furthermore,to analyse the relationship between the surface water and groundwater,also quantify the karst water moving mechanism and process under high degree of heterogeneity.QMG subostream system is in bosom of QingMuguan anticline of Jin Yun mountain,it is a typical study type in Chongqing hydro-geological study.Based on the actual observed data from May 2007 to April 2008,then use HSPF model to simulate the hydrological process,the following work have been conducted in this thesis:(1) Building basic database of study area though GIS,then analyse and reclassify the DEM and landuse maps.(2) After a large number of investigations in field,we find out the distributing of swallow holes and depression,we also ascertain the watershed boundaries;Though tracer tests,relationship between some swallow holes has been proved;(3) Compute the enormous hydrological and meteorological data.(4) Using the BASINS3.1 to divide the watershed into sub-basins and compute the characteristics of the sub-basins for the preparation,then run the HSPF model during a short time period(July 2007) to simulate the heavy rainfall-runoff behavior and in a long sequences from May 2007 to April 2008,at last,we get ideal results,so we complete a preliminary exploration in karst valley groundwater hydrology.Main results:(1) QMG sub-streams flow is similar with surface water.The flow of sub-streams is large and quick,it is sensitivity to the rain.Because of the geological structure,it forms a close groundwater network,the rain is the mainly water supply,the flow is discharged from the outlet at last.(2) Dividing the karst watershed is very important to the hydrological modeling.Based on the inhomogeneous surface condition(e.g.terrain,depression,swallow holes and landuse,etc.) and meteorological factors(e.g,rainfall and temperature,etc.),the QMG watershed is divided into 8 subbasins with the watershed declineation in Basins.(3) After the rainfall-runoff modeling to QMG sub-stream,the simulated flow result is good,and the average Nash coefficient of modeling result is 0.752,this result shows the HSPF model is feasible to simulate the karst sub-stream,but the model is more sensitive to the rain,and the simulated flow is larger than observed flow,the simulated flow curve declines slower.