Request for Proposal | Engineering Service Procurement
RFP 23-87:
2D Stormwater Model
A technical summary of procurement for professional engineering services strictly concerning the Meadow & Rivanna Watersheds within the USA, focusing on comprehensive PCSWMM modeling and floodplain analysis.
Awarding Body & Municipal History
- City of Charlottesville, USA: The principal awarding entity for RFP 23-87 is the City of Charlottesville, specifically acting through its Department of Public Works, Engineering Division. The purpose of this Request for Proposal (RFP) is to solicit sealed proposals from qualified firms to establish a long-term contract via a competitive negotiation process. This procurement focuses exclusively on the purchase of highly specialized professional engineering services needed to execute a complex 2D Stormwater Management Model and its array of related technical services for the local geography.
- Historical Foundation (2008 USACE Partnership): The City of Charlottesville possesses a deep, established history with comprehensive stormwater analytics. In 2008, the municipality entered into a significant partnership with the United States Army Corps of Engineers (USACE). Through this collaboration, they successfully developed a foundational, comprehensive stormwater model utilizing the PCSWMM 5.01.11 software environment. This historic model effectively represented a critical portion of the City's overall stormwater management inventory across three distinct watersheds: Moores Creek, Meadow Creek, and the Rivanna River.
- Initial Management Objectives: The core design mandate of the original 2008 modeling initiative was to deliberately produce a thoroughly updated technical basis for the City's sweeping stormwater management program. By establishing this baseline, municipal engineers and infrastructure planners could systematically deploy empirical data to make sound, highly effective management decisions regarding public investments and capital improvements spanning multiple decades.
- 2023 Grant Execution & Expansion: Recognizing the rapidly evolving needs of the municipality and shifting environmental parameters, the City of Charlottesville proactively sought to expand its technological capabilities. In January 2023, the City successfully executed a new, targeted grant agreement sourced through a dedicated local funding framework. The explicit purpose of this recent 2023 grant agreement was to aggressively expand the geographic scope of the legacy modeling efforts to encompass the remainder of the City's complex topography, heavily prioritizing the Urban Rivanna and Meadow Creek watersheds.
- Procurement Administration: As an institutional process, RFP 23-87 outlines strict administrative guidelines for participating engineering firms. Following its official issue date of March 20, 2023, the Department of Public Works requires that all sealed proposals be formally received by the closing date of April 25, 2023. The contract value itself is not fixed or pre-published as a placeholder within the RFP document; rather, the precise financial commitment will be determined entirely through the competitive negotiation protocols established under the City's procurement framework.
Project Description & Technical Scope
- Area of Interest & 2D Model Deployment: The geographic area of interest defined within the grant application and the RFP focuses strictly on the portions of the Meadow Creek and Urban Rivanna watersheds situated within the Charlottesville City limits. This specific footprint covers an approximate area of 6.5 square miles of municipal territory. The central objective is the comprehensive development of a state-of-the-art two-dimensional (2D) model (or multiple integrated models) built natively within the PCSWMM environment.
- Infrastructure Representation & 2D Mesh Construction: The chosen engineering consultant is mandated to deploy the absolute best available methodology and empirical data. The scope requires that the proposed model exhaustively represent the storm sewer network, critically including both public and private grey infrastructure, as well as all active receiving channels. A highly technical element involves building a sophisticated 2D mesh overlay. This mesh is designed specifically to identify complex overflow paths triggered by undersized conveyance systems, thereby pinpointing exact geographic areas that remain severely vulnerable to catastrophic flooding during storm events that exceed the defined level of service for the current sewer system.
- Data Aggregation Framework: To facilitate this robust analysis, the City is supplying an extensive array of datasets. This includes a 2023 geospatial inventory of storm sewer lines, structures, and stream centerlines, though the RFP explicitly cautions that this contains limited asset data. Additional provisions include sub-catchment delineations established in 2010, an impervious cover overlay updated in 2022, roadway and building footprint overlays from 2022, and meticulously defined 2022 parcel boundaries. Furthermore, the City provides a comprehensive log of drainage issue locations documented between the years 2018 and 2023 to provide historical context of system failures.
- Supporting Master Plans & Reports: Beyond raw GIS data, the engineering consultant will receive deep institutional literature to guide the modeling. This includes the original 2008 City-wide PCSWMM Model, the corresponding 2008 Stormwater Master Plan (complete with its highly technical PCSWMM memo), and twelve independent field investigation reports associated with the Capital Improvement Plan (CIP) prioritization efforts generated between 2017 and 2023. Crucially, the City is also providing DRAFT FEMA HEC-RAS models covering Meadow Creek and the Rivanna River (developed in 2022), alongside the overarching DRAFT City of Charlottesville Phase I Flood Resiliency Plan established in 2023.
- Supplemental Survey Data Acquisition: Despite the wealth of provided documentation, the scope recognizes that existing data alone is insufficient. The RFP dictates that independent, targeted survey data will be actively required in highly select locations scattered throughout the 6.5-square-mile watershed. This granular field surveying is an absolute prerequisite to verify the accuracy of the provided GIS inventory and to inject a necessary, heightened level of detail into the 2D mesh, ultimately ensuring the accuracy and reliability of the final modeling results.
- Defining Flood Vulnerabilities (Future Uses): The intended future uses of this completed model are vast and critical to the City's infrastructure resilience. The primary future use revolves around the rigorous definition of flood vulnerabilities. This process will systematically include the deep analysis of several diverse design storms, spanning the spectrum from high-frequency 2-year events all the way to severe 100-year disaster events, applying climate-influenced curves across multiple simulated scenarios to account for changing environmental patterns.
- Diagnostic Capability & Capacity Assessment: Operationally, the model must be utilized to identify the current level of service functioning across all existing municipal infrastructure. By establishing this baseline, the City can determine the exact spatial scope of capacity issues across both watersheds. The tool will specifically identify discrete areas—categorized heavily by impacted roadways and standing buildings—that are rendered highly vulnerable to flooding directly due to overflow pathways caused by systemic bypasses to the legacy infrastructure, or simply due to their geographic proximity to open channels.
- Climate Trends & Depth Quantification: To physically protect the citizenry, a key scope objective is to precisely quantify the theoretical depth of water that accumulates on critical roadways, especially focusing on hydraulic crossings and naturally low-lying geographic areas. Finally, the model is engineered to identify long-term, shifting potential trends in widespread floodplain expansion resulting directly from volatile, climate-influenced storm events over the coming decades.
Technical Evaluation & Validation Criteria
Model Validation & Delivery Protocols
The engineering deliverables undergo rigorous technical evaluation based on specific parameters outlined in the RFP text, particularly focusing on validation methods in a geographically complex, un-gauged environment:
- Validation Environment: The City explicitly recognizes that the 6.5-square-mile area of interest acutely lacks permanent gauge installations and formally recorded high water marks. Consequently, standard calibration utilizing isolated, specific historical storm events is impossible.
- Alternative Validation Methodologies: To ensure technical competency, the winning firm must pursue significant alternative validation efforts. This strictly includes applying the Virginia Department of Transportation (VDOT) hydraulic grade line (HGL) methodology at selected, critical infrastructure locations.
- HEC-RAS Comparative Analysis: A core technical evaluation metric requires the consultant to directly compare the newly generated Meadow Creek flow and runoff estimates against the existing regulatory HEC-RAS models provided via the DRAFT FEMA documentation.
- Empirical Correlation: A secondary validation layer involves the direct evaluation of the historically reported drainage issues (drawn from the 2018-2023 dataset) by systematically comparing those physical incident logs against the theoretical runoff generated within the proposed model during mathematically frequent storm events.
- Model Deliverable Submissions: The final deliverables must include the fully functional PCSWMM model accompanied by exhaustive source notes. Furthermore, a highly technical memo detailing all inputs, reference data, and the applied methodology is mandated.
- Community-Facing Output & Documentation: The firm must produce a comprehensive final report detailing the model results and high-resolution figures, specifically formatted and structured to be easily understood by a community-wide municipal audience. Multiple mapped figures identifying flood vulnerabilities across the vast array of design storm scenarios are strictly required.
- Hardcopy Requirements: The initial proposal protocol required the submission of one (1) printed document marked “Original” alongside three (3) exact printed copies, plus an accompanying electronic copy provided on a physical CD formatted in either Microsoft Word or standard PDF.
Technical Callouts
PCSWMM
A dynamic rainfall-runoff simulation model used comprehensively for single-event or long-term simulation of runoff quantity and quality. The 2008 municipal model utilized version 5.01.11.
USACE
The United States Army Corps of Engineers. An essential federal engineering and logistics agency that partnered directly with Charlottesville during the original 2008 foundational watershed study.
2D Mesh Framework
A highly advanced computational grid required by the RFP to systematically identify complex overflow paths across undersized stormwater conveyance systems throughout the city limits.
VDOT HGL Methodology
The Virginia Department of Transportation's Hydraulic Grade Line calculations. Mandated within this RFP as an alternative technical validation strategy due to the complete lack of physical high-water gauge installations.
HEC-RAS & FEMA Modeling
The Hydrologic Engineering Center's River Analysis System. DRAFT 2022 models from the Federal Emergency Management Agency are provided to the consultant as a critical comparative baseline for Meadow Creek flow validations.
CIP Prioritization
Capital Improvement Plan. Refers to the municipal funding mechanism; the RFP integrates 12 distinct field investigation reports generated for CIP assessments between 2017 and 2023 to inform the new grid model.
GAYA CAPITAL
DOCUMENT REF: RFP-23-87-CVILLE