Sedimentation and drawdown-induced habitat degradation limits reproduction of structure-associated fishes in flood control reservoirs. Littoral habitat enhancement can be accomplished by planting fast growing crops during winter, when lakebeds are exposed, to provide fish habitat during spring flooding. It remains unclear if species of crops differ in their submerged persistence or habitat quality to fish. I submerged six species of cool-season annual crops in mesocosms and monitored plant architecture over time. Adult plantings of two grasses persisted long enough to potentially be used by juvenile fishes in reservoirs. To assess the habitat quality provided by crops, I evaluated selection by juvenile Bluegills and adult Largemouth Bass in outdoor mesocosms. Bluegills selected Balansa Clover the most and Largemouth Bass selected annual Ryegrass. Results suggest some clovers may provide nursery habitat but degrade rapidly once submerged and dense annual grasses persist well and provide favorable habitat for prey and predator fish.

<p>In the first part, the pressureless gas dynamic system with source (body force) is examined and solved by using Shadow Waves. The source represents gravity and Shadow Wave solution (containing the delta function) shows acceleration (contrary to shocks, for example). In the second part, one will nd numerical calculations that conrms the above results.</p> / <p>Rad je posvecen analizi modela gasa bez pritiska uz dodatak izvora. Model je resen koriscenjem senka talasa. U ovom slucaju, izvor predstavlja uticaj gravitacije na cestice u modelu. Za razliku od udarnih talasa, talasi senke koje sadrze delta funkciju, krecu se ubrzano pod gravitacionim uticajem. U drugom delu rada su naprevljeni numericki eksperimenti koji potvrdjuju teoijske rezultate.</p>