tailieunhanh - WETLAND AND WATER RESOURCE MODELING AND ASSESSMENT: A Watershed Perspective - Chapter 18

Đặc trưng bởi một bảng nước nông (Sharitz và Batzer 1999), các vùng đất ngập nước là cảnh quan chuyển tiếp giữa các hệ thống nước mở cửa và mặt đất vùng cao. Họ cung cấp nhiều chức năng hệ sinh thái quan trọng và các giá trị, chẳng hạn như kiểm soát lũ lụt, nước ngầm, trầm tích và duy trì / ổn định, chất gây ô nhiễm dinh dưỡng môi trường sống / chuyển đổi loại bỏ, và cá và động vật hoang dã và đa dạng (Mitsch và Gosselink 2000). Đất ngập nước có xu hướng được. | Part V Watershed Assessment and Management 2008 by Taylor Francis Group LLC 18 Geospatial Decision Models for Assessing the Vulnerability of Wetlands to Potential Human Impacts Wei Wayne Ji and Jia Ma INTRODUCTION Characterized by a shallow water table Sharitz and Batzer 1999 wetlands are transitional landscapes between open water systems and terrestrial uplands. They provide many crucial ecosystem functions and values such as flood control groundwater recharge sediment and pollutant retention stabilization nutrient removal transfor-mation and fish and wildlife habitat and diversity Mitsch and Gosselink 2000 . Wetlands are prone to be filled in drained or ponded for a variety of human uses including stream channelization and maintenance urban development transportation improvement or conversion to agricultural uses Dodds 2002 . To protect wetland resources many laws and regulatory programs have been established. Among them the Clean Water Act CWA Section 404 is the primary federal law aiming to maintain and restore the chemical physical and biological integrity of the wetlands in the United States. It authorizes . federal agencies mainly the . Army Corps of Engineers to issue permits for the discharge of dredged or fill material into the navigable waters at specific disposal sites including wetlands USACE http www. cw cecwo reg . To comprehensively evaluate individual or cumulative impacts of human activities on existing wetlands a regulatory permit assessment requires quickly retrievable environmental and socioeconomic data and more importantly a scientifically justifiable evaluation framework for analyzing those data. In recent decades GIS techniques have been increasingly used to facilitate the data management and visualization in regulatory wetland assessments or permit reviews aiming to improve the efficiency of the permit assessment process. A pilot decision supporting GIS for the permit analysis was developed in the early