Development of a quantitative evaluation procedure for revelment blocks based on aquatic organisms preservation efficiency

1.利用新设计的水道对护岸块体进行相对评价通过设置两个面对面的护岸块体模型的水道，考察了护坡块体的相对鱼类偏好。我们发现，护岸块在50厘米/秒以上的高速运动中具有避鱼的作用。当速度较高时，最好选择开度较小的块体。在滑块的下游端有狭缝开口的滑块不是首选。低速区出露的植物比地块更受欢迎。碎石筑成的河岸是小鱼的最爱。块体周围环境条件分析收集不同流量下块体周围的流速、水流湍动等物理条件，建立偏好曲线，计算适宜度指数。区块周围水流模拟模型的建立建立了考虑空气混合的水流模拟模型。利用该模型计算了高流量区块周围和内部的水流情况。结论当流速大于50 cm/s时，我们的偏好方程可以解释观察到的鱼的分布，但有时它不能解释低流速条件下的鱼的分布。因此，我们的偏好方程可以用来定量评估护岸块体作为鱼类避难所的价值。

1. Relative evaluation of revetment blocks by using a newly designed water courseRelative fish preference for revetment blocks was examined by using a water course which equipped two revetment block models facing each other. We found that revetment blocks have a function as a fish refuge for high velocity of over 50cm/sec. When the velocity is high, blocks with smaller opening were preferred. A block which has a slit opening at the downstream end of the block was not preferred. Emerged plants in a low velocity area are more preferred than blocks. River bank made of gravels are preferred by small fish.2. Analysis of environmental condition around the blocksVelocity, water turbulence, and other physical condition around the blocks for various flow rate were collected to build up preference curves and to calculate suitability index.3. Development of current simulation model around the blocksA current simulation model with air mixing was built. By using the model, current condition around and inside the blocks with high flow rate were calculated.4. ConclusionOur preference equation could explain the observed fish distribution when flow rate was over 50cm/sec, although it sometimes failed to explain the fish distribution in low flow rate conditions. Thus our preference equation can be used to evaluate the value of revetment blocks as fish refuge from flood quantitatively.