Groundwater Numerical Simulation On Ganjingzi District In Dalian

Groundwater, one of the important supplementary water sources, was over-pumped as more water quantity was demanded with the rapid development of the economies in some areas in Dalian. It resulted in the decline of groundwater table, seawater intrusion and so on. There’s no time to delay to manage the groundwater pumping in this city. For this reason, it needs to simulate the groundwater and evaluate the groundwater resource in this area. Distributed groundwater numerical simulation model is efficient to research on dynamic of groundwater.Aiming at problems when multipurpose utilization of groundwater in Dalian, the main studies were drawn as follows:(1) Groundwater system in Ganjingzi district was chosen to be a key study object. Based on the analysis of hydro-geological condition about this study area, two-dimensional homogeneous isotropic unsteady flow numerical simulating model was constructed. The initial flow field was computed by steady flow method using the data of average precipitation and exploitation quantity from2006to2007. According to lithological characters and borehole data, boundaries of study area and parameter sub areas were assigned. With the trial-and-error method, parameters of the model were identified by Modflow2000module which is embedded in Visual Modflow software. The identification period was from2008to2009. After the parameters were identified, the model was tested by data of precipitation and exploitation in2010.(2) According to the data series of precipitation from1990to2004and the current groundwater developing conditions, the groundwater flow fields of study area during2011and2025have been predicted.(3) According to water assessment results (2011a-2025a) and water using plan,3scenes were made, and the groundwater flow field changes were predicted.With the analysis on cones of depression and water balance budgets of3scenes, the conclusions were drawn as follows: (1) In simulated period(2011a-2025a), total recharge31380.05×104m3, total discharge is29347.93×104m3. Natural recharge is about2092×104m3, and recharge modulus is about10.55×104m3/(km2·a). In the condition of the current groundwater exploitation, the storage of groundwater is increasing, but the cone of depression can’t disappear.(2)Stopping exploitation in limestone mine is good for recovery of groundwater. Increasing pumping rates of else wells can reduce part of evaporation and discharge fluxes to ocean. Groundwater resource can be made full use by these measures.(3) Comparing these results, Scene3which includes stopping exploitation in limestone mine and increasing pumping rates of else wells which are far away from sea is more better for sustainable utilization of groundwater resource than other scenes.