Study on River Ecological Water Requirement Based on Water Quantity Model and Water Quality Model

Abstract

Study on eco-environmental water requirement was of great significance in the planning and regulation of ecological water system, and the regional optimization of water resources. The river ecological water requirement is the core of the study. In this paper the meaning of eco-environmental water requirement and ecological status of lake are discussed. Based on the environmental flow of natural ecosystem, the water quantity model is built referring to the Montana law and year guarantee setting method; on basis of the analysis of the relationship among environmental flows of river requirements, the efficiency of water resource usage, the consumption coefficient, and the concentration of waste water elimination, the water quantity and water quality calculation method of the environmental flows river requirements in social and economic system is developed by reference to the controlled object inversion model (COIM). With the two models, the river ecological situation and the corresponding water demand were investigated. Results shows that, to achieve the goal which the river eco-environmental situation is safe for Zhengzhou city, the river ecological water requirement is 52.6, 57.9, 60.5, and 63.1 million m3 in 2005, 2010, 2015 and 2020, respectively; to achieve the target which the river's eco-environmental situation is healthy for Zhengzhou city, the river's ecological water requirement is 287, 300, 313 million m3 in 2010, 2015, and 2020, respectively. Considering the water resources condition in the planning years for Zhengzhou city, it is necessary to increase external water of 160, 124, 155 million m3 to get healthy river in 2010, 2015 and 2020, respectively.Keywords-river ecological water requirement; water quantity model; water quality model; water resource allocation

Study on Water Replacement Characteristics of Xinghai Lake Wetland Based on Landscape Water Quality Objectives

“…The convective diffusion equation in MIKE21 is used to compute the water replacement cycle, and an exponential decay function based on the change in concentration is used to calculate the tracer concentration decay rate (11).…”

“…From equation (11), the concentration has decayed to e −1 , or 37% of the initial concentration, when t = Tf(V/Q); therefore, the water change cycle is defined as the time required for the remaining concentration to decrease to 37% of the initial concentration [6].…”

“…The ecology is fragile, with low biodiversity and insufficient biological richness of microbes, plants, and fish. There are currently fewer studies on water demand computation and the water replacement cycle from the perspective of the water quality-volume balance of landscape water bodies than there are studies on Xinghai Lake's evaluation of water environment quality and analysis of pollution sources [11].…”