Description

1) Fayetteville NC City-Wide Watershed Program – Challenges and Solutions
Alicia Lanier, PE, City of Fayetteville, AliciaLanier@FayettevilleNC.gov
Co-presenters: Sheila Thomas-Ambat; SheilaThomasAmbat@FayettevilleNC.gov; Morgan McIlwain; mdm@freese.com

Abstract: City of Fayetteville NC City-wide Watershed Master Plan program is now in its fourth year of development. In 2019 City leaders embarked on an ambitious $13M Watershed Master Plan program to better understand the magnitude and severity of flooding across the entire city and proactively develop flood mitigation projects. Leaders understood that a comprehensive evaluation would support resiliency by providing a pool of prioritized projects for both short-and long-term implementation. This effort will apply resources equitably, identify creative regional-scale projects, and leveraging inter-governmental and cross-departmental collaborations. The program is unique in that the foundation was established within four years, to include an intensive rebuild of the city stormwater geodatabase, a city-wide stormwater asset field survey, parallel 1D and 2D modeling efforts by several consulting teams, scoring and ranking concern areas, and development thus far of over 200 projects. Out of the 15 watersheds in the City, master plans for four watersheds have been completed for this Priority 1 phase with projects now under design, while master plans for four others are in development. The aggressive schedule, large team, and complex and ever-evolving program requirements have yielded remarkable successes, while understandably creating challenges. This presentation provides an overview of the program, the successes, and specific approaches taken to overcome the inevitable challenges. At the heart of being able to overcome the challenges is the continuous collaboration amongst all team members with steady involvement by the City. The success of the program relies on the ability to reflect at regular intervals in order to communicate, adapt and respond to change; show continuous progress by delivering measurable results; and strive to honor the commitment to value people over process.

2) Providing Holistic Flooding Solutions in Urban Areas: the Fayetteville NC Story
Mark Van Auken, PE, Arcadis, mark.vanauken@arcadis.com
Co-presenters: Scott Brookhart, Arcadis, Scott.Brookhart@arcadis.com; Alicia Lanier, City of Fayetteville, AliciaLanier@FayettevilleNC.gov

Abstract: Many communities across the U.S. suffer from routine and severe flooding due to a combination of riverine impacts and old, undersized stormwater collection systems, especially in urban areas. But how many communities have the opportunity to develop detailed hydrologic and hydraulic models of both systems on a watershed scale? How many also use these models to transform their downtown with holistic flood mitigation solutions that truly redefine urban drainage? The City of Fayetteville NC had the vision and financial commitment. A Master Plan was prepared for Blounts Creek watershed that included detailed 1D and 2D hydrologic and hydraulic models using HEC-HMS/HEC-RAS for the primary (riverine) system and ICM for the secondary (collection) system; performing a field assessment of high priority stream reaches; and identifying issues and problem areas using the modeling and field assessment results to inform required mitigation with new proposed drainage solutions. One of the proposed solutions that provides the greatest flood mitigation and risk reduction is the Person/Russell St Bridges Improvements and Stream Enhancement project. It is a large-scale primary system improvement that provides flooding relief to a significant number of low to moderate income homes, allows future secondary system improvements to meet level of service requirements, and provides an opportunity for community enhancements and nature-based solutions within the stream corridor to improve resiliency. This presentation will step through the overall program and vision of the City in establishing and implementing the watershed master plan program. It will discuss the process used to develop, validate, and integrate the 1D and 2D riverine and collection system models including several project innovations to improve efficiency and accuracy. It will also detail the process used and proposed project developed to cost effectively provide holistic improvements, mitigate stormwater flooding and improve livability in downtown Fayetteville.

3) Watershed Planning: Using Data Driven Modeling to Prioritize Protection and Mitigation
Jenny Fleming, VHB, jfleming@vhb.com
Co-presenters: Ivy Huang, PhD, EI; Courtney Carpenter, PE, CFM

Abstract: This presentation will demonstrate how the use of spatial modeling in ArcGIS can be used to evaluate the conditions of a watershed (e.g., water quality, habitat, hydrology), to link issues back to their underlying causes (e.g., indicators), and to recommend strategies to both preserve areas in good condition and to identify areas where mitigation action or water quality projects may serve the most benefit. The North Carolina Division of Mitigation Services (DMS) hired VHB to develop a Regional Watershed Plan (RWP) for parts of two 8-digit Hydrologic Unit Codes (HUCs) within the Cape Fear Watershed: The Haw River (03030002) and the Deep River (03030003). The study area covers approximately 620 square miles and twenty-two 12-digit HUCs. The objective of the RWP is to create a modeling strategy based on available data to evaluate the conditions of a watershed, link issues back to their underlying causes, and recommend strategies to preserve areas in good condition. Ultimately, this watershed plan will help DMS identify opportunities to mitigate sources of stressors to the three main functions of a watershed—hydrology, water quality, and habitat. In consultation with DMS, VHB developed a spatial modeling approach in ArcGIS using the best available data to evaluate the conditions of a watershed (e.g., water quality, habitat, hydrology), to link issues back to their underlying causes (e.g., indicators), and to recommend strategies to both preserve areas in good condition and to identify areas where mitigation actions may serve the most benefit. The focus of this presentation will be on the VHB's approach for identifying catchments with mitigation potential, called Focus Areas herein. These Focus Areas are often at-risk catchments, or catchments that may be in decline but where early action may improve current condition and prevent future losses. https://ncdenr.maps.arcgis.com/apps/webappviewer/index.html?id=7a5751caf43d45168f77eb68a61f1fc9