Performance evaluation of various evapotranspiration modeling scenarios based on METRIC method and climatic indexes.

Evapotranspiration (ET) is one of the most important factors controlling hydrologic, agricultural, and weather cycles. It also converts a large portion of rainfall into vapor, being known as the largest water flux from the earth into the atmosphere. Since ET is affected by many factors, such as land surface characteristics and climatic conditions, it undergoes considerable spatiotemporal variations, particularly at the watershed scale. Hence, to obtain a more accurate estimation of ET, it is required to identify homogenous and uniform regions, each represented by a meteorological station. In this study, three scenarios were proposed in order to identify homogenous regions to estimate ET based on METRIC method, and the scenarios were tested in Sefidrood Watershed in the north of Iran. The first scenario included only vegetation factor with one representative station for the entire case study watershed and ignored diverse conditions affecting ET across the watershed. The second scenario incorporated not only the vegetation factor but also the altitudinal variations of the watershed. In the second scenario, the watershed was divided into two distinct altitudinal sections, each with a representative station with a specific influenced area, with ET being estimated separately for each section. Finally, the third scenario incorporated the altitudinal and climatic variations. The results indicated that the second scenario performed better than two other scenarios in ET estimation. In other words, altitude and vegetation strongly influenced spatial and temporal distributions of ET, leading to considerable variations of it in the watershed.

Optimal Wastewater Loading under Conflicting Goals and Technology Limitations in a Riverine System.

This paper investigates a novel simulation-optimization (S-O) framework for identifying optimal treatment levels and treatment processes for multiple wastewater dischargers to rivers. A commonly used water quality simulation model, Qual2K, was linked to a Genetic Algorithm optimization model for exploration of relevant fuzzy objective-function formulations for addressing imprecision and conflicting goals of pollution control agencies and various dischargers. Results showed a dynamic flow dependence of optimal wastewater loading with good convergence to near global optimum. Explicit considerations of real-world technological limitations, which were developed here in a new S-O framework, led to better compromise solutions between conflicting goals than those identified within traditional S-O frameworks. The newly developed framework, in addition to being more technologically realistic, is also less complicated and converges on solutions more rapidly than traditional frameworks. This technique marks a significant step forward for development of holistic, riverscape-based approaches that balance the conflicting needs of the stakeholders.

Relationship between benthic macroinvertebrate bio-indices and physicochemical parameters of water: a tool for water resources managers.

The ecosystem health of rivers downstream of dams is among the issues that has become focus of attention of many researchers particularly in the recent years. This paper aims to deal with the question, how the environmental health of a river ecosystem can be addressed in water resources planning and management studies. In this study, different parameters affecting the ecosystem of river-reservoir systems, as well as various biological components of river ecosystems have been studied and among them, benthic macro-invertebrates have been selected. Among various bio-indices, biodiversity indices have been selected as the evaluation tool. The case study of this research is Aboulabbas River in Khuzestan province in Iran. The relationship between the biodiversity indices and physicochemical parameters have been studied using correlation analysis, Principal Component Analysis (PCA), and Genetic Programming (GP). Margalef index was selected as the appropriate bio-index for the studied catchment area. The relationship found in this study for the first time between the Margalef bio-index and physicochemical parameters of water in the Aboulabbas River has proved to be a useful tool for water resources managers to assess the ecosystem status when only physicochemical properties of water are known.

Developing a master plan for hospital solid waste management: a case study.

Disposal of about 1750tons of solid wastes per day is the result of a rapid population growth in the province of Khuzestan in the south west of Iran. Most of these wastes, especially hospital solid wastes which have contributed to the pollution of the environment in the study area, are not properly managed considering environmental standards and regulations. In this paper, the framework of a master plan for managing hospital solid wastes is proposed considering different criteria which are usually used for evaluating the pollution of hospital solid waste loads. The effectiveness of the management schemes is also evaluated. In order to rank the hospitals and determine the share of each hospital in the total hospital solid waste pollution load, a multiple criteria decision making technique, namely analytical hierarchy process (AHP), is used. A set of projects are proposed for solid waste pollution control and reduction in the proposed framework. It is partially applied for hospital solid waste management in the province of Khuzestan, Iran. The results have shown that the hospitals located near the capital city of the province, Ahvaz, produce more than 43% of the total hospital solid waste pollution load of the province. The results have also shown the importance of improving management techniques rather than building new facilities. The proposed methodology is used to formulate a master plan for hospital solid waste management.