Projects & Studies
|Drainage Area||Watershed Population||Open Stream Miles||Primary Streams|
|212 Sq. Miles||528,720||308 Miles||
> Do you live in a FEMA mapped floodplain?
> Monitor rainfall and stream levels (NEW! Near Real-time inundation mapping)
The Greens Bayou watershed is located in north Harris County and encompasses portions of the cities of Houston and Humble. The upper reach of Greens Bayou flows in an eastward direction and the lower reach flows southward into the Houston Ship Channel. The watershed covers about 212 square miles and includes four primary streams: Greens Bayou, Halls Bayou (fact sheet), Garners Bayou and Reinhardt Bayou.
There are about 308 miles of open streams, including the primary streams and tributary channels. Based on the 2010 U.S. Census, the estimated population of the Greens Bayou watershed is 528,720.
Greens Bayou Wetlands Mitigation Bank at Sunset.
Flooding of homes and businesses along Greens Bayou and its tributaries has occurred numerous times in the last two decades, with recent devastating flood levels throughout the watershed brought on by Tropical Storm Allison in 2001. Significant floodplains and high-density development have combined to cause high damages during frequent flood events. Additionally, storm surges can influence flooding levels along the lower 10 miles of the watershed.
Most of the watershed is highly developed. Some large areas between U.S. 59 and I-10 remain undeveloped. Construction of new residential and commercial developments is expected to continue in the northern and western regions of the watershed.
The District is implementing the first wetlands mitigation bank in Harris County, which is located near the confluence of Greens and Garners Bayou. The mitigation bank provides compensating wetlands credits for projects that cannot avoid disturbing wetlands and qualify for credits. The wetlands bank and reaches of the bayou that pass through dense woodlands are highly sensitive and support diverse wildlife habitats. Downstream of I-10, the channel flowline is below mean sea level and this reach of the bayou is tidally influenced.