GroMoPo Metadata for Lower Palar River basin model

A three-dimensional mathematical model to simulate regional groundwater flow was used in the lower Palar River basin, in southern India. The study area is characterised by heavy abstraction of groundwater for agricultural, industrial and drinking water supplies. There are three major pumping stations on the riverbed apart from a number of wells distributed over the area. The model simulates groundwater flow over an area of about 392 km(2) with 70 rows, 40 columns, and two layers. The model simulated a transient-state condition for the period 1991-2001. The model was calibrated for steady- and transient-state conditions. There was a reasonable match between the computed and observed heads. The transient model was run until the year 2010 to forecast groundwater flow under various scenarios of overpumping and less recharge. Based on the modelling results, it is shown that the aquifer system is stable at the present rate of pumping, excepting for a few locations along the coast where the groundwater head drops from 0.4 to 1.81 m below sea level during the dry seasons. Further, there was a decline in the groundwater head by 0.9 to 2.4 m below sea level in the eastern part of the area when the aquifer system was subjected to an additional groundwater withdrawal of 2 million gallons per day (MGD) at a major pumping station.本研究针对印度南部帕拉尔河（Palar River）下游流域，采用三维数学模型（three-dimensional mathematical model）模拟区域地下水流（groundwater flow）运动。研究区域内，农业、工业及饮用水供应对地下水的开采强度极高。该区域内除分布有多处水井外，河床之上还设有三座大型抽水站。该模型模拟的地下水流覆盖面积约392 km²，模型网格包含70行、40列，共两层。模型以1991年至2001年为模拟时段，表征非稳定流（transient-state condition）状态。模型分别针对稳定流（steady-state condition）与非稳定流状态进行了率定。模拟计算得到的测压水头与实测水头之间吻合度良好。随后将非稳定流模型运行至2010年，以预测不同超采与补给减少情景下的地下水流变化。基于模拟结果可知，当前开采强度下，研究区含水层系统（aquifer system）整体处于稳定状态，但沿海岸线的部分区域例外：旱季时这些区域的地下水位水头较海平面低0.4~1.81 m。此外，若某大型抽水站每日额外抽取200万加仑（MGD）地下水，研究区东部区域的地下水位水头将较海平面下降0.9~2.4 m。