荆江分洪区在分洪时期,我们需要取得分洪区内的流量及水位变化过程等资料。但由於:一、断面太宽,最狭处也有2,600公尺以上;二、堤身弯曲度很大,设立基线困难,同时在分洪时堤面狭小,去年分洪期测流时就只能用100公尺长的基线来控制这样大的断面;三、因断面太宽,用望远镜经纬仪等找自标有困难,用六分仪或肉眼又看不见,如再用一般河流的测验方法就更困难,测得的资料也不可靠。沙市水文分站根据具体情况,决定 Jingjiang flood diversion flood diversion area in the period, we need to obtain flood diversion area flow and water level change process and other information. However, due to: First, the section is too wide, the most narrow at 2,600 meters or more; Second, the great curvature of the dike, the establishment of a baseline difficult, while dike dike narrow, Last year flood measurement can only be used when 100 Third, due to the section is too wide, with a telescopic theodolite to find themselves difficult, with sextants or the naked eye can not see, such as re-use the general method of testing the river is even more difficult , The measured data is not reliable. Shashi hydrological stations according to the specific circumstances, the decision