HOUSTON – (By Michael F. Bloom, P.E.) – In the Houston area, traditional development practices have relied on concrete parking lots, paved streets, and precast concrete storm sewers to move rainwater quickly to end-of-pipe detention basins. These basins collect runoff and release it into nearby streams or bayous at controlled rates to reduce downstream flooding.
Typical subdivisions are often disconnected from nearby streams. Homes and businesses are organized around detention basins, which frequently hold permanent pools and are presented as manicured lakes to future residents.
There is a viable alternative: natural drainage systems, commonly called low impact development (LID).
Natural drainage systems mimic the behavior of headwater streams and bayous, better reflecting how water flows across the landscape. They extend existing stream and bayou corridors into developments, creating open-space amenities that include creeks, trails, and parks.
By replacing underground concrete storm sewers with open, vegetated conveyance—swales, vegetated medians, and biofiltration features—water leaves the site more slowly. Slower runoff reduces the required detention volume, which can increase buildable area and lot yield, lower infrastructure costs, and create attractive open-space amenities such as trails and parks that add value for homeowners.
Natural drainage also serves as a market differentiator. Many buyers now prefer neighborhoods that feel natural and environmentally friendly. LID features can frame trail systems—one of the most requested amenities—and balance a manicured entrance landscape with more natural, rustic corridors that lead away from homes.
Under the Texas Water Code, natural drainage systems can qualify as drainage utilities. That allows developers to receive reimbursement for construction costs through special districts funded by tax-exempt municipal bond proceeds.
Here are several local examples demonstrating how natural drainage has been implemented.
Audubon Grove, a large-lot single-family subdivision in Springwoods Village near the new ExxonMobil campus, contains 57 lots on about 24 acres. Designed by Costello, Inc. for Taylor Morrison, the project incorporates trail systems that follow natural swales (see Figure 1).
Roadways in Audubon Grove are constructed without curbs so stormwater drains directly into swales. Front-yard swales are finished with cobbles for a refined appearance that still functions as part of the drainage system (see Figure 2).
Camellia, a single-family subdivision in Fort Bend County, spans about 50 acres with 323 lots. Designed by EHRA for Legend Homes, the neighborhood features roadways that slope toward depressed vegetated center medians. The outside edge of the roads uses traditional curbs while the inner edge is curbless to allow sheet flow into the swale system.
Figures 3 and 4 illustrate the site overview and the roadway with vegetated medians. The Camellia project realized significant economic benefits: natural drainage reduced infrastructure requirements, lowered detention needs, increased lot yield, and reduced costs.
Stonebrook Estates in the Champions/Spring area, designed by R. G. Miller Engineers, Inc. and Aguirre & Fields for Terra Visions, includes 135 lots on about 51 acres (see Figure 5). Approximately 70% of the site uses natural drainage features—landscaped swales and biofiltration systems that function as high-rate sand filters to remove pollutants. The remaining portions rely on conventional storm sewers.
Roads in Stonebrook are designed with one-sided slopes and curbs but incorporate “false back inlets” that route water to vegetated swales instead of costly underground pipes (see Figure 6). Using natural drainage lowered the required site detention by 24%, which in turn increased lot yield.
The business case for natural drainage in the Houston region is compelling. Benefits include:
- Reduced detention volume needed to meet floodplain regulations;
- Increased lot yield and buildable area;
- Lower drainage infrastructure costs compared with extensive underground piping;
- Eligibility for cost reimbursement through special districts under state law;
- More homes with direct access to open space and natural amenities, supporting higher sale prices;
- Alignment with market demand for environmentally sensitive, natural-feeling communities; and
- Distinctive community design that differentiates developments in a competitive market.
For further guidance on low impact development in the region, consult the Houston-Galveston Area Council’s regional guide to LID design.
AUTHOR: Michael Bloom, P.E., manages the Sustainability Practice at R. G. Miller Engineers, Inc. He helps clients improve economic, social, and environmental outcomes for their projects, drawing on 24 years of experience in planning, design, and permitting related to stormwater management and the Clean Water Act. Bloom is a nationally recognized expert on natural drainage systems. Follow his professional updates on social media.
*Footnote: Ring, J. 2015. Talking Dollars and Sense: LID Construction Costs. Presented at the ASCE International LID Conference. Houston, Texas. January.
Jan. 4, 2017 – Content by R.G. Miller Engineers Inc.