黄河冲积平原灌溉入渗研究

Research on the Irrigation Infiltration in the Yellow River Alluvial Plain

黄河冲积平原面积广大，农田灌溉频繁，灌水量大，在地下水资源评价时对灌溉入渗系数取值困难。本文在现场灌溉入渗试验的基础上，分析包气带岩性及结构、水位埋深、灌溉水量对灌溉入渗系数的影响，总结提出了多种条件下灌溉入渗系数的取值范围。在单位灌水量40～60m3／亩和水位埋深小于4m、4～8m、大于8m的井灌区中，当包气带岩性为粉土、粉砂时，灌溉入渗系数可分别取值0．21～O．10、0．10—0．05、0．05～0；当包气带岩性夹有粉质粘土层时，灌溉入渗系数可分别取值0．15～0．09、0.09—0．05、0．05～0。在单位灌水量较大的渠灌区，灌溉入渗系数可按单位灌水量的增大倍数而增加，由此为黄河冲积平原区地下水补给量计算中灌溉入渗系数的确定提供了依据。

The Yellow River alluvial plain is a large area, whose farmland irrigation is very frequency that wasted a large amount of water. It is hard to obtain irrigation infiltration coefficient values when the groundwater resourc- es are evaluated. In this paper, on the basis of the field irrigation infiltration test, the lithology, structure, water lev- el, and irrigation water in the vadose zone impacting on the irrigation infiltration coefficient was summarized, and the range of irrigation infiltration coefficient on various conditions is proposed. In the well irrigated area, the unit of irrigation water is 240 - 360 m3 per acre and the groundwater level range is 〈4 m, 4 - 8 m and〉 8 m. If there is floury soil and silt in the vadose zone, the value rang of irrigation coefficient infiltration is 0.21 - 0.10,0.10 0.05,0.05 - 0, respectively; If it mixed with silty clay layer in the vadose zone, the value rang of irrigation coeffi- cient infiltration is 0.15 - 0.09,0.09 - 0.05,0.05 - 0, respectively. In the canal irrigation district where the unit of irrigation is big, irrigation coefficient infiltration is increased with the multiple increase of unit irrigation water. This conclusion provide the basis for determining the irrigation coefficient infiltration when calculate the quantity of groundwater recharge in the area of the yellow river alluvial plain.