Application Of Water Quantity And Quality Model Based On SOBEK In Songhua River Basin

Along with the influence of the people's activity,the Song Huajiang River basin deterioration in water quality situation is seriously day by day. Comparing with water quality goal of the water function region,beside water quality is better in the upstream section of river,water quality on the quite partial monitor section cannot satisfy the corresponding request. This article is aim at studying movement regularity of the water flow and the water environmental transformation in this basin network. SOBEK software can reflect the Songhua River basin state of each riverway objectively , which has provided the certain technical support for the more thoroughgoing research this area water volume and quality condition for the future. SOBEK is an integrated software package for river,urban or rural management. The integrated approach makes SOBEK a valuable instrument for flood forecasting, navigation, optimising drainage systems, controlling irrigation systems, reservoir operation,sewer overflow design,ground water level control, river morphology regulation, and water quality control. SOBEK has stable computation,extremely fast speed, high visible degree. SOBEK-Rural gives regional water managers a high-quality tool for modeling irrigation systems,drainage systems, natural streams in lowlands and hilly areas. Applications are typically related to optimizing agricultural production flood control, irrigation, canal automation,reservoir operation, and water quality control. According to the Songhua River basin nature and the humanities condition(concrete hydrology terrain characteristic , the distribution regularity of water resources time and space and development situation and so on),defining model area scope and cutting the grid cells,this article establishs the one-dimensional unconstant flow water volume model,which uses Sobek-Rural one-dimensional water volume and quality model,inputs needs the essential data document according to the Saint-Venant equations. According to the characteristic of Songhua River basin,this article establishes the one-dimensional water quality model in view of BOD and DO simultaneously. Assigning the various parameter,the model is applied to carry on the recognition and confirmation of the model until fitting the precision. Finally,this article forecasts BOD and DO density change situation base this model,and has analysed the forecast result.Colligate the full text,we may attain following conclusion:(1)Using SOBEK software,may obtain the basin all sections of river water level,the change regularity of flux and the distribution of water quality time and space,the software has realized the computed result (the flow field and the density field) simulation.(2) SOBEK one-dimensional water flow and quality simulation system, not only has considered the model particularity,but also manifested the accuracy of digitized riverway,direct-viewing displays the model computation result,which is the powerful tool about simulating and studying water flow and quality in wide range.(3) The mathematics physics foundation of one-dimensional unconstant flow value simulation is Saint-Venant equations and its finite difference equation. SOBEK software has discretized on Saint-Venant equations by implicit difference format,caused the equation fully numerical solution to become possibly, thus the equation obtained a more widespread application(4) The fitting result illustrate fully one-dimensional network water volume and quality model which is suitable to the Songhua River basin, which can use in the hydrodynamics characteristic analysis and water quality simulation study for each kind of goal.(5) The establishment of the water quality model can provide the ration relation for the pollutant discharge and water quality analysis in the river. As a result of water resource system complexity,the people are difficult in using the method of fall the massive pollutant or stop discharging the pollutant to experiment the water resource purify ability and the transformation regularity, the physical model method is applied to achieve the certain authenticity difficultly which must consume massive manpower and the physical resource. But using the mathematical model method has a bigger flexibility and compatibility,which can complete computation comparison on each kind of plan in the short time and has the superiority when carries the contrast analysis on many plans specially.(6) The result of the water quality forecast indicated: The river in Songhua River basin water quality change tendency as follows: The Nenjiang River water quality is all worse in abundant time and smooth time; The second Songhua River water quality is worse as a whole, the water quality is not different in abundant and smooth time largely; The Songhua River main reach water quality in abundant time is good relative to smooth time.