SIMULATING WATER DYNAMICS IN AGRICULTURAL STORMWATER IMPOUNDMENTS FOR IRRIGATION WATER SUPPLY

摘要

The hydrology of an impoundment in an agricultural grove in southern Florida was studied to assess its potential use as a water supply source. The MIKE SHE/MIKE 11 integrated hydrologic model was used to simulate the various hydrologic processes and their interactions. The model was calibrated and validated for water levels inside the impoundment and in a ditch outside the impoundment. Model evaluation results showed that the model could be used for assessing water retention alternatives with root mean square error (RMSE) values ranging from 0.03 to 0.25 m. Several structural and managerial alternatives were identified and evaluated to increase water retention volume and time. The alternatives include lining the impoundment, lining only the embankment and the inner distribution canal with 15 and 30 cm liner thicknesses, and pumping water regularly from the surrounding ditch to the impoundment. All alternatives were compared to the present condition. Lining the entire impoundment with clay provided ten weeks of additional irrigation from September to May. Lining the embankment and the inner canal of the impoundment provided up to four weeks of additional irrigation. Extending the regular pumping for a month after the wet season resulted in the reservoir being filled to full capacity during that month. The modeling study shows that clay-lining impoundments could provide an additional source of irrigation