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Safe Yield in a Coastal Ground‐Water Regime
Author(s) -
Mull Rolf,
Battermanna G.
Publication year - 1980
Publication title -
groundwater
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.84
H-Index - 94
eISSN - 1745-6584
pISSN - 0017-467X
DOI - 10.1111/j.1745-6584.1980.tb03421.x
Subject(s) - groundwater recharge , water table , drawdown (hydrology) , groundwater , hydrology (agriculture) , estuary , drainage , aquifer , geology , water level , inflow , environmental science , drainage system (geomorphology) , water cycle , precipitation , oceanography , geotechnical engineering , ecology , physics , cartography , meteorology , geography , biology
The limiting factors for the, safe yield in the investigated coastal area were sea water along the coastline and saline water at about 250 m below sea level. Both types of salt water will intrude into existing wells, when the potential heads are changed sufficiently by increasing pumping. Besides this, the recharge rate due to precipitation affects the potential head. In a hilly central part of the region, water infiltrates into the ground, and seeps to the saturated zone where it flows some kilometers to flat marshy regions near the coast and estuaries. There it comes up to drainage systems near the land surface (long cycle). In the marshy region the infiltrated water exfiltrates into drains and ditches after a short passage of some meters in the upper zone of the aquifer (short cycle). The calibration of a digital ground‐water model gave the existing ground‐water budget. The prognostication of the safe yield was based on these results. The most interesting problem of model calculations was to take into consideration the dependence of the recharge rate on the depth of the ground‐water table below the land surface. If the ground‐water level is lowered by pumping below the drainage system, the short cycle will be interrupted. The downward seeping water flows within a saturated zone to the wells and affects the potential head. The greater the drawdown, the greater is the recharge rate. The depression of the water table by pumping is compensated up to a certain degree.