The Harris County Flood Control District is in the midst of completing a $1.5 million management study aimed at creating a unified approach to handling overflow issues in the Cypress Creek and Addicks Reservoir watersheds.

The population within the study area—the entire Addicks watershed and the portion of the Cypress Creek watershed downstream of Hwy. 290—is expected to double in the next 50 years to 680,000 people. Before the population increase happens, the district wants to minimize flooding issues in the area, said Mike Talbott, district director.

"As the area around the Cypress Creek watershed develops, it will change the runoff characteristics," he said. "That could influence how much water comes over the divide. We're trying to look at, as growth continues in the Addicks tributaries, what needs to be done to consider overflow."

Flooding that occurs around certain portions of Cypress Creek during heavy rains happens in large part because Harris County did not have means of regulating land development until the flood insurance program came about in the early '70s, Talbott said.

"With all of the development that occurred prior to the detailed flood insurance rate maps, they didn't know what risk they were dealing with," he said. "Subdivisions older than 30 years near our natural channels in the Cypress Creek watershed are typically going to have some legacy flooding problems."

The management study involves the Addicks Reservoir watershed since that is the area in which water from Cypress Creek drains.

"The reservoirs were built to protect the people downstream, so adding more water to reservoirs is something we want to make sure is considered," Talbott said.

Several organizations aside from the HCFCD are involved in the management study, including the West Houston Association, Bayou Preservation Association, City of Houston and Katy Prairie Conservancy. Those groups formed a steering committee last year to balance the needs of developers, business owners and environmental concerns and create goals related to flood mitigation.

"It may involve criteria, policy or actual projects, but it's about having a uniform plan that all those involved can work from," Talbott said. "It will provide expectations for land developers and owners in the area to know what the conditions and criteria are in advance."

State of the Addicks and Barker reservoirs

• The Addicks Reservoir watershed extends from the western side of Hwy. 290 down into western Harris County, while the Cypress Creek watershed spans northwest Harris County from Cypress to Spring
• The watersheds drain into the Barker and Addicks reservoirs, which were built in the 1940s to protect downtown Houston from major flooding events
• In the spring of 2009, heavy rainfall in the amount of nearly 8 inches fell on northwestern Harris County, which resulted in the flooding of portions of Eldridge Parkway and Hwy. 6 from the Addicks Reservoir
• The U.S. Army Corp of Engineers, which built the reservoirs, designated them as being "extremely high risk" due to two structural areas of concern, but they are not in imminent danger of failing, according to the organization
• However, increased development is a concern in northwestern Harris County, as it contributes to flooding issues

Source: Harris County Flood Control District and U.S. Army Corp of Engineers