The Research On Flow Characteristics And Dissolved Oxygen Of Urban River Bottomland

Urban river is an important part in urban ecological system as an importantresource and environmental carrier is the mark of the city, highlighting the spiritualityof the city. China’s urban river regulation has already changed from “river trainingproject” to “ecological river management”, the construction of ecological river is thenew way which spring up rapidly around the world. In this paper, the urban riverbottomland of river flow characteristics and dissolved oxygen were studied, and thephysical model experiment system of indoor rectangular glass tank was developed tostudy turbulence characteristics and dissolved oxygen content distribution along thesection when no river bottomland running river, river island running river, river islandwith beach running river operating mode.The experimental results show that: In terms of water level, the water leveldistribution of three mode changes significantly, its trend is very similarly, and theriver mainstream showed a gradual increase with increasing flow rate, water levelsalong the cross-section is stepwise reduced. The minimum water appears in section11in the front of river island, states the tail water level minimum value is generallyappear in section20, water level is almost equal and symmetrical feature distributionin the straight or slightly curved braided rivers.; About water depth, the water depth inriver island channel value distribution generally centered on mid-stream like a funnelshaped. Beach symmetrically arranged in the river, from the origin of200cm to300cmand400cm to500cm section depth changes, the same values within the scope of itsdepth is smaller than other section; Aspects of flow velocity, the river mainstreamvelocity exhibiting typical linear jumbled waves and the section along the distributionof velocity values were reduced. Beside flow maximum appearing in the straight orslightly curved braided rivers, on the top and bottom beach area velocity variationhave same trend, the two "big in the middle, both sides of the small" size of the areawith a typical velocity values appear in the river, around this area belt velocity valuesfrom cross section flow rate value is big, and increases with the increase of the slope. In the field of dissolved oxygen, when river island running, the section of the riveralong the uneven distribution of dissolved oxygen, but river island in the river flowcan play the role of shaping the riverbed also constraints the flow, in the distance of the origin of270cm to330cm and370cm to400cm sections appear within thescope of dissolved oxygen content in the smaller area with ease, the latter is oftenthe minimum content of dissolved oxygen in the river. There is no significant effecton the river channel after joins the beach, and have little difference with the former.