Towne Lake Master Planned Community

EHRA Engineering provided surveying, design engineering, and construction management services for the development of the 2,400-acre multi-use lake community in northwest Harris County, known as Towne Lake.  The development centers around a 325-acre lake / detention basin which is used as an amenity system for the residents, and meets the stormwater detention requirements.  EHRA Engineering has engineered and constructed this “GHBA 2012 Master Planned Community of the Year” from the onset, and the development is now considered a “destination for living and recreation.” EHRA performed a hydrologic and hydraulic analysis for the ultimate development conditions of the master-planned community which spans Addicks Reservoir and Cypress Creek watersheds.  The basin was analyzed such that two separate outfall structures discharge the developed runoff from the basin into each watershed and show no adverse impacts to existing watersheds.

The design included a 360-LF box culvert stormwater outfall designed to maintain a static lake level for recreation purposes and to drain the 325-acre lake discharging a maximum of 540 CFS a 100-year storm. Water quality measures have also been incorporated into the outfall system. An arc shaped floatable collection screen approximately 150 feet in length was constructed to restrict floating debris from entering public creeks and streams. EHRA also performed a volumetric analysis to determine the volume of developed runoff draining to the Addicks Reservoir and Cypress Creek watersheds. A portion of the development was constructed within the effective floodplain limits along Cypress Creek. The impacts of floodplain fill within the Cypress Creek watershed were mitigated within the lake/detention basin system and analyzed as part of a hydraulic impact analysis for Cypress Creek to show no adverse impact to the flood hazard conditions.

Floodplain conveyance impacts due to the proposed floodplain fill were mitigated within a proposed mitigation basin along Cypress Creek. EHRA prepared a Conditional Letter of Map Revision (CLOMR) documenting the hydraulic impact analysis along Cypress Creek, which also included a future Greenhouse Road bridge that crosses Cypress Creek. Excavation of the lake required moving over one million CY of dirt, spreading the material across the property for development. Installation of a clay liner was required in order to maintain lake levels and minimize the volume of water lost. The excavation involved eight different contractors totaling 250,000 sq. yds. of excavation equaling approximately $24.0M. The excavation also included a contract between developer and Sprint Sand & Clay (SS&C) to only mine sand. SS&C excavated +/-190,000 CY in 9-12-month period. EHRA advertised the project after performing an as-built survey after SS&C moved offsite. The topsoil was left on site, just pushed to the areas where excavation for sand was not anticipated.

Towne Lake Named Houston Landmark

Houston Business Journal