WATER-SAVING AND POLLUTION-REDUCING METHOD FOR WATER CIRCULATION USE IN IRRIGATION AND DRAINAGE COUPLED ECOLOGICAL IRRIGATION DISTRICT IN FLAT AREAS

摘要

A water-saving and pollution-reducing method for irrigation and drainage coupled water circulation use suitable for a flat ecological irrigation district, wherein an irrigation district drainage period and an irrigation district water need period are comprised; during the irrigation district drainage period, field drained water enters a cyclically-adjusting wetland reservoir (1) through a drainage ditch, sediments, pesticides and harmful heavy-metal substances are intercepted and purified through a submerged plant zone (15) and an ecological wetland purification island (16) system, and nitrogen and phosphorus nutrient substances are treated, thus reducing the damage done by drainage to the bodies of water of rivers and lakes; during the irrigation district water need period, bodies of water in the cyclically-adjusting wetland reservoir (1) are extracted by a water extraction pump (2) and distributed to irrigation district farmlands (12), thus increasing the utilization efficiency of water resources, wherein the residual nitrogen and phosphorus nutrient substances may also be needed for the growth parts of crops.