Tag Archive for: sheet flow

Cogdill Video Shows Overland Sheet Flow From Clear-Cut Area Pouring into Elm Grove; HCFCD Issues Report on Flood

Edy and Ricky Cogdill live across the street from Abel Vera on Village Springs Drive. Both the Veras and the Cogdills live at the end of the street. Their properties butts up against the new development on the other side of the Montgomery County line seen in the background of this video. Edy Cogdill shot the video on May 7, 2019. It shows what hydrologists call “overland sheet flow.”

A small part of the 262-acre development that drains toward Elm Grove. Sheet flow from this clear-cut area ran off into Elm Grove. On top of street flooding, it caused house flooding.

Edy Cogdill shot this video will standing on her front porch with an umbrella. As the floodwaters came out of the clear-cut area to their north, the water hit the Cogdill house and started moving sideways. Toward the end of this short video, Edy pans right. You can see the the flow coming out of the new development and rushing down Village Springs Drive past the dead-end barrier.

The water from the development added to street flooding in progress. As a result, homes flooded.

Video courtesy of Edy and Ricky Cogdill on Village Springs Drive in Elm Grove. Shot on May 7, 2019.

Harris County Flood Control Issues Report on Storm

Jeff Lindner of Harris County Flood Control issued a report this morning on last weeks two flash flooding events.

The report says: “130 structures were flooded in the Elm Groove Village subdivision in the northern portions of Kingwood on Tuesday evening. HCFCD staff investigated this area on Wednesday, May 8th and determined that the flooding was potentially caused by development upstream in Montgomery County that sent large volumes of sheetflow into the subdivision and Taylor Gully (G103-80-03.1). The isolated nature of the heavy rainfall on Tuesday afternoon prevented more widespread flooding impacts.”

Lindner also cautioned that the number of affected structures may change; the City of Houston is still verifying the number. Earlier media reports of 400 homes flooding may have overstated the problem.

2- to 50-Year Official Rainfall Rates

The Harris County Flood Control Report on the storm also states that on May 7: “Heavy rainfall rates developed due to slow storm motions over northeast Harris County including the Humble and Kingwood areas. A 30-min rate of 2.9 inches was recorded at US 59 and the West Fork of the San Jacinto River and a 1 hour rate of 4.0 inches. A 6-hr rainfall rate of 7.9 inches was recorded at the East Fork of the San Jacinto River and FM 1485. Rainfall rates between the 15-min and 6- hr time periods on Tuesday afternoon and evening averaged between a 2-yr and 50-yr frequency over the extreme northeast portions of Harris into southeast Montgomery Counties. This rainfall was relatively isolated in the far northeast portions of Harris County and the Kingwood area.” 

Posted by Bob Rehak on 5/13/2019

622 Days since Hurricane Harvey