Study on the Minimum and Appropriate Instream Ecological Flow in Yitong River Based on Tennant Method

It has been very urgent situation that the Yitong River ecological environment gradually worsening and aquatic ecological environment restore, especially the city wastewater and wastewater emissions increased gradually, making the river self purification capacity decreased gradually. In order to maintain the basic ecological functions of rivers, it is very important to study the instream minimum and appropriate ecological flow. The Yitong River main control section's (Yitong Hydrology Station and Nongan Hydrologic Station) minimum and appropriate ecological flow is calculated based on Tennant method. After the Tennant method of flow standard is modified, the ecological water demand is 0.17×10⁸m³, minimum in Yitong station, the suitable ecological water requirement is 0.23×10⁸m³, respectively, representing average annual flow in Yitong station 26.3% and 36.3 %. The minimum ecological water requirement of Nongan station is 0.77×10⁸m³, the suitable ecological water requirement is 1.13×10⁸m³, respectively, representing the Nong2 an station mean annual runoff 21.3% and 31.3%, providing a reference for ecological regulation of Yitong river ecological protection and restoration.