USACE CWMS - Cape Fear 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 Cape Fear watershed headwaters are in the Piedmont geographic region characterized by relatively low, rolling hills extending into the Upper Coastal and Lower Coastal plains characterized predominantly by wetlands in the middle to southeast portions of the watershed. Elevations range from 900 feet in the western hills to sea level at the mouth of the Cape Fear River in Wilmington. Average annual precipitation in the Cape Fear watershed ranges from 42 inches in Greensboro near the head waters to 57 inches in Wilmington on the coast. The Greensboro area average annual snowfall of 9 inches. However, runoff due to snowmelt is generally not a concern in this watershed.

Within the Cape Fear basin, there is one USACE reservoir project. The project is the B. Everett Jordan Dam and Lake on the Haw River approximately 4 miles upstream of the confluence of the Deep River which creates the Cape Fear River. The project purposes include flood control, water supply, recreation, fish and wildlife enhancement, and augmentation of low flows for the purposes of pollution abatement and water-quality control in the Cape Fear River Basin.

Other locks and dams on the Cape Fear River include Buckhorn Lake Dam, Huske Lock and Dam, Lock and Dam #1 and Lock and Dam #2. Buckhorn Lake Dam creates a backwater effect at the tailrace of the B. Everett Jordan Dam. The Shearon Harris Lake Dam is located on Buckhorn Creek and serves the Shearon Harris Nuclear Power Plant, Unit 1 located in New Hill, NC. The plant is operated by Carolina Power & Light Company.

A few of the notable tributaries to the Cape Fear River include Turnbull Creek, Harrisons Creek, Rockfish
Creek, Little River, Upper Little River, Buckhorn Creek, Deep River and Haw River. Tributaries to the Haw River upstream of the B. Everett Jordan Dam include New Hope River, Cane Creek, Big Alamance Creek, Back Creek, Stony Creek, and Reedy Fork.

The key inflow gages in the basin include Haw River at Haw River, Haw River near Bynum, Morgan
Creek near Chapel Hill and New Hope Creek near Blands. Key gages downstream of B. Everett Jordan Dam are Deep River at Moncure, Cape Fear River at Lillington and Cape Fear River at Fayetteville.

During flood control operations, the primary objective of B. Everett Jordan reservoir is to control floods along the Cape Fear River, particularly in the vicinity of Fayetteville. The basic plan of operation is to maintain a normal pool elevation of 216 feet, mean sea level (msl), by releasing inflows up to nondamage stages in the downstream reaches of the river. The non-damage stage at Fayetteville is 31 feet at the river gage. The effects of runoff from uncontrolled drainage areas on Fayetteville stages is forecast by monitoring flows at the Deep River at Moncure gage, the Cape Fear River at Lillington gage and the Cape Fear River at Fayetteville gage. Flows from the Deep River are particularly significant.

An objective of water quality control at B. Everett Jordan Lake is meeting the North Carolina and Environmental Protection Agency (EPA) standards for both the impounded water and the river water below the dam. For low flow regulation, 94,600 acre-feet (67%) of water quality storage is reserved in the conservation pool of Jordan Lake for release during critically dry periods. 45,800 acre-feet (33%) of the conservation pool storage is reserved for water quality. A required minimum instantaneous flow of 40 cfs is maintained immediately below the dam. Releases are made from the conservation pool storage allocated to water quality as necessary to maintain a minimum of 600 cfs as measured at the Lillington stream gage. Occasionally, the flow at Lillington may drop below 600 cfs because of variations in river flows induced by small hydroelectric plants located on the Deep River.

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，用于辅助流域水管理工作：
- GeoHMS（地理空间水文建模扩展，Geospatial Hydrologic Modeling Extension）
- ResSIM（水库系统模拟，Reservoir System Simulation）
- RAS（河道分析系统，River Analysis System）
- FIA（洪水影响分析，Flood Impact Analysis）

开普菲尔（Cape Fear）流域的源头位于皮埃蒙特（Piedmont）地理区域，该区域以低矮起伏的丘陵为特征，延伸至上海岸平原与下海岸平原；流域中南部至东南部区域则以湿地为主要地貌类型。流域内海拔从西部丘陵的900英尺，直至威尔明顿市境内开普菲尔河河口的海平面。开普菲尔流域的年平均降水量从源头附近格林斯伯勒的42英寸，至沿海威尔明顿的57英寸不等。格林斯伯勒地区年平均降雪量为9英寸，但该流域的融雪径流通常不会引发水管理相关问题。

在开普菲尔流域内，仅有一处美国陆军工程兵团（United States Army Corps of Engineers, USACE）主导的水库工程：位于霍河（Haw River）上的B·埃弗雷特·约旦大坝与约旦湖，该大坝地处深河（Deep River）汇口上游约4英里处，而深河与霍河汇流后形成开普菲尔河。该工程的功能包括防洪、供水、休闲娱乐、鱼类与野生动物栖息地保护，以及为开普菲尔河流域的污染治理与水质控制进行低流量补水。

开普菲尔河上的其他船闸与大坝包括巴克霍恩湖大坝、赫斯克船闸大坝、1号船闸大坝以及2号船闸大坝。巴克霍恩湖大坝会在B·埃弗雷特·约旦大坝的尾水区产生回水效应。希伦·哈里斯湖大坝建于巴克霍恩溪上，为北卡罗来纳州纽希尔市的希伦·哈里斯核电站1号机组提供服务，该电站由卡罗来纳电力与照明公司（Carolina Power & Light Company）运营。

开普菲尔河的主要支流包括特恩布尔溪、哈里森溪、岩鱼溪、小河、上小河、巴克霍恩溪、深河与霍河。B·埃弗雷特·约旦大坝上游的霍河支流包括新希望河、凯恩溪、大阿拉芒斯溪、巴克溪、斯通尼溪与里迪福克溪。

流域内主要的入流监测站包括：霍河霍河段监测站、比纳姆附近霍河段监测站、教堂山附近摩根溪监测站，以及布兰兹附近新希望溪监测站。B·埃弗雷特·约旦大坝下游的关键监测站包括：门瑟尔深河段监测站、利灵顿开普菲尔河段监测站，以及费耶特维尔开普菲尔河段监测站。

在防洪调度期间，B·埃弗雷特·约旦水库的核心目标是管控开普菲尔河沿线的洪水，尤其是费耶特维尔周边区域的洪水。其基础运行方案为：通过向下游河道放行至无损害水位的来水，维持水库正常蓄水位为216英尺（平均海平面，mean sea level, msl）。费耶特维尔河段的无损害水位为河道监测站显示的31英尺。通过监测门瑟尔深河段、利灵顿开普菲尔河段以及费耶特维尔开普菲尔河段的流量，可预测未管控汇水区径流对费耶特维尔水位的影响，其中深河的来流影响尤为显著。

B·埃弗雷特·约旦湖的水质管控目标为：使库区蓄水与大坝下游河道水质均符合北卡罗来纳州与美国环境保护署（Environmental Protection Agency, EPA）的标准。为满足低流量调控需求，约旦湖调节库容中预留了94600英亩-英尺（占比67%）的蓄水量，用于极端干旱时期的下泄补水；另有45800英亩-英尺（占比33%）的调节库容专供水质管控使用。大坝下游即刻河段需维持不低于40立方英尺每秒的瞬时最小流量。必要时，将从专供水质管控的调节库容中放水，以维持利灵顿河道监测站测得的流量不低于600立方英尺每秒。但由于深河沿岸小型水力发电厂引发的河道流量波动，利灵顿监测站的流量偶尔会降至600立方英尺每秒以下。