introduction: better use of water and soil resources in paddy fields, increase in rice production and farmer's income, installation of subsurface drainage system is necessary. the main goalof these systems, are aeration conditions improvement prevention of water logging, yield increase, land use increase and multiuse of the land. in different countries, installation of subsurface drainage cause...

the system dynamics technique is an object-oriented approach that studies and manages complex feedback systems. its merits include the friendly and easy development and improvement of a model. it is also used as a decision tool for engineering problems. in this paper, the system dynamics technique was used to simulate the performance of a subsurface drainage system in an unsteady state. the mod...

The Monongahela River Basin has an extensive history of fossil fuel development, including coal mining and natural gas extraction. In late summer 2008, total dissolved solids (TDS) concentrations exceeding the United States Environmental Protection Agency′s (EPA) secondary drinking water standards were detected. After determining source, a voluntary discharge management plan (VDMP) was develope...

Over the last ten years there has been an increasing awareness of the impacts of uncontrolled biological waste discharge into the receiving waters. The types of impact such discharges produce in the receiving waters are discussed. Early standards were based on overseas research but there is now a substantial body of New Zealand based work. Initial research concentrated on dairy shed discharges ...

introduction water quality refers to the chemical, physical and biological characteristics of water. it is a measure of the condition of water relative to the requirements of one or more biotic species and or to any human need or purpose. it is most frequently used by reference to a set of standards against which compliance can be assessed. the most common standards used to assess water quality...

introduction: side weir structures are extensively used in hydraulic engineering, irrigation and environmental engineering, and it usually consists of a main weir and a lateral channel. side weirs are also used as an emergency structure. this structure is installed on one side or both sides of the main channel to divert the flow from the main channel to the side channel. lateral outflow takes p...