§ 4.1. Introduction

This chapter will touch on the aspects of planning in regard to drainage.

Planning for different components of a project is crucial to the success of the project, whether the project is a residential subdivision, commercial development, or a capital improvement project. The Design Engineer must consider the impacts to the existing drainage systems as well as the aesthetics of the planned improvements.

The City of San Antonio had commissioned a study in the 1950s to determine drainage improvement needs throughout the City of San Antonio (City Drainage Master Plan). These improvements cost hundreds of millions of dollars and a number of the improvements were funded over the years through bond programs and other funding sources. In more recent years, following the development of the Digital Flood Insurance Rate Maps (DFIRM) for Bexar County, a number of additional flooding issues were realized throughout Bexar County. These flooding issues were studied and a Regional Drainage Master Plan was developed to address these issues.

The following should be considered during the development of the project:

Multi-use facilities are encouraged, but not required. Multi-use facilities allow for water quality, satisfy National Pollutant Discharge Elimination System (NPDES) requirements, enhance ground water recharge, provide open space, provide recreation or other amenities, and/or provide habitat. Multi-use facilities may be utilized so long as the facility meets the standards set forth in Chapter 2.8 of this manual and does not increase the rate or volume of erosion above that which would result from the use of a facility without multiple uses. Utilization of multi-use detention facilities to alleviate existing flooding problems, enhance and provide amenities for older neighborhoods, and support the revitalization of economically depressed areas is encouraged in public and private redevelopment initiatives.