Montgomery County Comprehensive Flood Management Plan

To ensure that the County is better prepared to address flooding issues, work is underway on the development of a Comprehensive Flood Management Plan (CFMP). The CFMP is a multiyear effort designed to improve the County’s ability to prevent, prepare for, respond to, and recover from flooding. The CFMP will include policy and programmatic components and technical studies.

The policy and programmatic efforts will examine the County’s laws, regulations, development and design standards, programs, budgets, etc. that address (or perhaps contribute to) various aspects of flooding and develop recommendations for changing them.

The technical studies will involve detailed hydraulic and hydrologic modeling to characterize flood risks and vulnerabilities in selected watersheds in the County. This information will be used to identify flood mitigation measures that the County could implement to minimize the potential for flooding in specific locations. Implementation of individual flood mitigation projects would occur through the County’s Capital Improvements Program (CIP). In addition, the information provided through the technical studies could be used to guide policy issues. For example, if the modeling shows a particular area is subject to potentially significant flooding under future precipitation and development conditions, the County may want to enact specific development or design standards to minimize flooding impacts to existing and new properties in that area.

The CFMP consists of three phases:

Phase 1

Completed in May 2023, consisted of (1) an initial review of the County’s laws, regulations, development and design standards, and other policy related aspects of the County flood-related activity, which resulted in recommendations related to continuing to engage on these issues, and (2) an initial review of watershed-related data to identify watersheds to prioritize for detailed hydraulic and hydrologic modeling in Phase 2.

Phase 2

Scheduled to run through the end of 2026, will involve (1) continued discussion of flood-related policy issues and the development of recommendations related to those policies, and (2) detailed hydraulic and hydrologic modeling of 11 watersheds covering approximately 100,000 acres (156 square miles) in the County to identify flood risks and vulnerabilities under a range of future precipitation and development scenarios, and the initial identification of flood mitigation measures to reduce flooding.

Phase 3

Phase 3 will involve implementation of identified flood mitigation projects under the County’s Capital Improvements Program (CIP). Projects included in the CIP would be subject to approval by the County Council and would include input from the public.