Drainage & Erosion Control Manual Update
The purpose of the Drainage and Erosion Control Design Manual is to establish standard principles and practices for the planning, design, construction, maintenance, and management of stormwater drainage, erosion control, and water quality facilities within the City of West Lake Hills and its ETJ.
The City Engineer, Walter P. Moore, is performing a review of the Code of Ordinances drainage requirements and the Drainage and Erosion Control Manual for additional amendments in the fall. Due to reoccurring questions staff have received regarding drainage study requirements, specific amendments are being recommended ahead of the comprehensive update.
The Zoning and Planning Commission reviewed draft language at the July 16, 2023 meeting and provided feedback to Staff. The language of proposed changes to Section 2.4 Stormwater Mitigation would provide definition when drainage should be studied from pre-developed conditions vs existing conditions. The proposed language provides clarification consistent with the current application of requirements for drainage review. This amendment would not change the requirements for which development category (Type I, II, III) must be submitted.
Proposed Amendment Language Discussed at ZAPCO (Additions in Red Italics):
A. Pre-Developed Conditions. Refers to the development condition within the watershed prior to any development. This should be used as the baseline for assessing the impact of all new development. New development is defined as a project that is reconstructing or adding more than 50% of the existing impervious cover on the site.
B. Existing Conditions. Refers to current development conditions in the watershed and on site. This shall be used as the baseline for assessing the impact of redevelopment projects. Redevelopment is defined as a project that is reconstructing or adding less than or equal to 50% of the existing impervious cover on the site.
Additional Recommended Updates:
A full review of the DECM is being conducted by staff and WPM. Once the comprehensive review and recommendations are prepared, they will be posted to this site, along with the schedule for review and adoption. At this point, no date is set for drainage manual amendment adoption.
(f) Amendments to the drainage and erosion control design manual may be recommended by city staff. Prior to approval by the city administrator, notification shall be given to the city council of all proposed amendments. The City Council may approve the amendment without further discussion or request the amendment be brought to City Council for review. Before an amendment to the drainage and erosion control design manual may be approved by the city the proposed amendment shall be posted on the city website for fourteen (14) days with contact information for interested residents to correspond with the city.
When the draft amendments are posted, a survey will be provided to collect feedback that will be submitted to City Council.