USACE CWMS - Genesee 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) Genesee River rises in the Allegheny Mountains in Potter County, PA, and flows generally north for about 157 river miles to empty into Lake Ontario at Rochester Harbor, NY. The basin is about 100 miles long and has a maximum width of about 40 miles. The total basin area is 2,466 square miles, of which 1,080 square miles is above the dam. The topography of the southern portion of the basin, above the dam, is steep and rugged, while the lower portion of the basin is gently rolling. Damaging floods on the Genesee Basin have occurred in all months of the year except August. Summer floods are generally localized, and are usually the result of unstable air conditions. Winter and spring floods are usually the result of frontal precipitation on saturated or frozen ground, or on melting snow cover, although floods have been caused from melting snow cover alone. Prevailing winds at various stations range from south to northwest. Average annual precipitation on the basin varies from approximately 25 to 40 inches, with sharp differences between the western rim and the central part of the valley. Mt. Morris Dam was authorized in 1944 and completed in 1951, and first used for flood regulation on November 24, 1951. Mt Morris Dam is located approximately 67 river miles above the mouth of the Genesee River in Livingston County, NY, and about 4 miles west of the village of Mt. Morris. Mt. Morris Dam is a concrete gravity dam whose primary purpose is reduction of flood damage in the lower Genesee River. The overall length of the dam is 1,028 feet, with a top width of 20 feet, bottom width of 212.8 feet, and maximum height above the streambed of 215 feet. The uncontrolled ogee overflow spillway is 550 feet long and located in the center of the dam with a crest elevation of 760.0 feet (NAVD 29). Nine rectangular outlet conduits, each with a 5 foot wide by 7 foot high minimum cross section, are located at the base of the spillway section. Mt. Morris Reservoir is contained entirely in the deep and narrow valley of the Genesee River between Mt. Morris and the lower Portage Falls. Below the falls, the river flows through a constricted valley for 1.5 miles then through a narrow canyon over 500 feet deep and 3 miles long known as the Portage High Banks. The next 5 miles are through the narrow St. Helena Valley and then through another gorge section, known as Mt. Morris Canyon, for 7 miles to the Mt. Morris Dam. At the top of flood control pool, elevation 760.0 feet (NAVD 29), the reservoir has a total length of approximately 17 miles and a maximum width of about ½ mile. The total storage at top of flood control pool is 337, 400 acre-feet. The area at full pool is 3,300 acres. The reservoir area is rugged and undeveloped, and approximately 50 percent wooded.美国陆军工程兵团水管理系统（Corps Water Management System, CWMS）包含四个相互关联的模型，用于辅助该流域的水管理工作： - 地理水文建模扩展工具（Geospatial Hydrologic Modeling Extension, GeoHMS） - 水库系统模拟工具（Reservoir System Simulation, ResSIM） - 河道分析系统（River Analysis System, RAS） - 洪水影响分析工具（Flood Impact Analysis, FIA） 杰纳西河（Genesee River）发源于宾夕法尼亚州波特县的阿利根尼山脉，干流大致向北流淌约157河道英里，最终在纽约州罗切斯特港注入安大略湖。该流域长约100英里，最大宽度约40英里，总流域面积为2466平方英里，其中坝址以上流域面积为1080平方英里。流域南部（坝址以上区域）地形陡峭崎岖，下游区域则地势平缓起伏。杰纳西流域的破坏性洪水全年均可发生，仅8月除外。夏季洪水多为局地性灾害，通常由大气不稳定条件引发；冬春季节洪水则多因锋面降水落在饱和或封冻地面，或是融雪所致，不过也存在仅由融雪引发洪水的情况。流域内各监测站的主导风向为南风至西北风。流域年平均降水量约25至40英寸，流域西部边缘与山谷中部的降水量差异显著。 莫里斯山坝（Mt. Morris Dam）于1944年获批立项，1951年竣工，并于同年11月24日首次用于防洪调度。该坝位于纽约州利文斯顿县杰纳西河河口以上约67河道英里处，距离莫里斯山村以西约4英里。莫里斯山坝为混凝土重力坝，核心功能是减轻杰纳西河下游的洪水灾害。坝体总长度为1028英尺，顶宽20英尺，底宽212.8英尺，河床以上最大高度为215英尺。坝体中部设有总长550英尺的无控制奥吉式溢洪道，堰顶高程为760.0英尺（北美垂直基准面29，NAVD 29）。溢洪段底部设有9条矩形泄水涵管，单条涵管的最小横断面尺寸为5英尺宽、7英尺高。 莫里斯山水库（Mt. Morris Reservoir）完全坐落于莫里斯山与下波蒂奇瀑布之间的杰纳西河幽深狭窄河谷中。瀑布下游，河流先流经一段1.5英里长的束窄河谷，随后进入一段长3英里、深度超过500英尺的狭窄峡谷，即波蒂奇高岸峡谷。此后的5英里河段流经狭窄的圣海伦娜河谷，再经过一段长7英里的峡谷河段——莫里斯山峡谷，最终抵达莫里斯山坝。在防洪控制库水位（高程760.0英尺，NAVD 29）下，水库总长度约17英里，最大宽度约0.5英里。防洪控制库水位对应的总库容为337400英亩-英尺，满库时水面面积为3300英亩。水库周边区域地形崎岖且未开发，约50%的区域为林地。