USACE CWMS - Big Sandy River Watershed

The Corps Water Management System (CWMS) includes four interrelated models to assist with water management for the basin:
- GeoHMS (Geospatial Hydrologic Modeling Extension)
- ResSIM (Reservoir System Simulation)
- RAS (River Analysis System)
- FIA (Flood Impact Analysis)

The Big Sandy River lies entirely within the State of Kentucky; however, the total watershed area of 4,283 square miles also drains portions of Virginia and West Virginia. Of the nearly 4,483 square miles that make up the basin, 54% is located in Kentucky, 23% is in West Virginia, and 23% is within Virginia. Big Sandy River is formed by the junction of Tug and Levisa Forks at Louisa, Kentucky, and flows in a general northerly direction for 26.83 miles to its junction with the Ohio River at Kenova, West Virginia and Catlettsburg, Kentucky. The river, along its entire length, forms a part of the boundary between the states of Kentucky and West Virginia. Levisa Fork and Tug Fork are the two largest tributaries of the Big Sandy River Basin draining 2325 and 1559 square miles, respectively, of the total basin. The Big Sandy Basin is irregular in shape, having a length of about 105 miles and a maximum east-west width of 91 miles.

The Big Sandy River Basin lies wholly within the physiographic province known as the Appalachian Plateau. The topography of the Big Sandy River watershed is generally rugged. The area is well dissected and has a total relief of about 3,300 feet. Over most of the area the main streams and their many tributaries flow in deep, narrow, sinuous valleys between steep-sided ridges. In the headwater regions the terrain is mountainous, whereas in the lower portion of the area the valleys are relatively wide and the hills are gentle and rounded, averaging about 300 feet in height.

The Big Sandy River Basin contains a wide variety of flooding problems ranging from flash floods in the upper portions of the basin; major community flood damage centers such as Williamson, Matewan, Pikeville, Prestonsburg, and Paintsville; and backwater flooding from the Ohio River in the lower portion of the basin. Basin runoff is highest during the winter months when storm rainfall may combine with snowmelt and when frozen or saturated ground can result in very low infiltration rates. Runoff is lowest during late summer and early fall when the ground is dry and infiltration losses are high. However, precipitation during these seasons may be quite heavy and of sufficient intensity to more than make up for the higher infiltration rates.

There are no large cities in the Big Sandy River Basin, and the rural areas are sparsely settled. The largest city in the basin is Pikeville, KY, one of only 8 cities in the basin with a population exceeding 3,000 people.

Four cities are protected by USACE local protection projects in the basin, they are Matewan, WV, Williamson, WV, Pikeville, KY, and Prestonburg, KY. The Big Sandy River is the only navigable waterway, used for the local coal industry as well as an oil refinery located on the river.

军团水资源管理系统（CWMS）集成了四个相互关联的模型，旨在协助流域的水资源管理：
- 地理水文模型扩展（GeoHMS）
- 水库系统仿真（ResSIM）
- 河流分析系统（RAS）
- 洪水影响分析（FIA）

大桑迪河完全位于肯塔基州境内；然而，总面积为4,283平方英里的流域也排除了弗吉尼亚州和西弗吉尼亚州的部分地区。构成流域的近4,483平方英里中，54%位于肯塔基州，23%位于西弗吉尼亚州，23%位于弗吉尼亚州。大桑迪河由特格和莱维斯 Forks 在肯塔基州路易莎交汇而成，大致向北流去，全长26.83英里，至其在西弗吉尼亚州肯诺瓦和肯塔基州卡特莱茨堡与俄亥俄河交汇处。河流在其全程中构成了肯塔基州和西弗吉尼亚州之间的边界。莱维斯 Fork 和特格 Fork 是大桑迪河流域的两个最大支流，分别排除了总面积2325平方英里和1559平方英里的流域。大桑迪河流域形状不规则，长度约为105英里，东西方向最大宽度为91英里。

大桑迪河流域位于被称为阿巴拉契亚高原的地理学区域。大桑迪河流域的地形总体上崎岖不平。该区域地形切割深刻，总海拔差约为3,300英尺。在大部分地区，主要河流及其众多支流在陡峭的山脊之间蜿蜒流淌，形成深邃、狭窄的峡谷。在源头地区，地形多山，而在区域的下游部分，山谷相对较宽，丘陵温和圆润，平均高度约为300英尺。

大桑迪河流域包含多种洪水问题，从流域上游的突发洪水；到如威廉森、梅特万、派克维尔、普雷斯顿堡和佩恩斯维尔等主要社区洪水损害中心；以及来自俄亥俄河的下游地区回水洪水。流域径流在冬季月份达到最高，此时风暴降雨可能与融雪相结合，或者冻结或饱和的土壤可能导致非常低的渗透率。径流在夏末和初秋最低，当时地面干燥，渗透损失较高。然而，这些季节的降水量可能相当大，强度足以抵消更高的渗透率。

大桑迪河流域内没有大城市，农村地区人口稀少。流域内最大的城市是派克维尔，肯塔基州，它是流域中仅有的8个城市之一，人口超过3,000人。

流域内有四个城市受到美国工程兵团（USACE）地方保护项目的保护，它们是梅特万（西弗吉尼亚州）、威廉森（西弗吉尼亚州）、派克维尔（肯塔基州）和普雷斯顿堡（肯塔基州）。大桑迪河是唯一可通航的水道，用于当地煤炭工业，以及河上的炼油厂。