Elm Grove Looks for Answers and Doesn't Have to Look Far

The hardest hit area from Tuesday’s storm seemed to be one that never flooded before: Elm Grove Village. Media have reported as many as 400 homes flooded there. As I drove down Elm Grove streets near the Harris/Montgomery County line, home after home had waterlogged trash, carpet, mattresses and furniture piled in front. Suddenly, I had eerie flashbacks to Harvey. Clusters of people in the street trading horror stories. Service trucks everywhere. Residents gaping at damage, consoling each other. People crying as they threw out prized belongings. Shock, sympathy, anger, fear all rolled into thousand-yard stares. Wondering what would come next with 8-12 more inches of rain on the way. But most of all, they were asking “Why?”

Why?

Here’s what I’ve been able to learn.

According to the residents I talked to, this area never flooded before…even during Harvey.
The storm drains were clear. City Councilman Dave Martin who was onsite this morning coordinating the City’s response showed me fiber optic video of clear storm sewers. Public Works could find no blockages near the flooded homes in Elm Grove.
Drone footage (below) shows there were no blockages in the ditch that services the area.
The rainfall intensity and duration on Tuesday both played a roll.
According to Martin, storm drains in this area are designed to handle 1/2 inch of rain per hour. However, Elm Grove received close to 10 inches during a 5 hour period on Tuesday.
A complicating factor was a new subdivision being built in Montgomery County (by a subsidiary of Perry Homes, Figure Four Partners LTD) that butts up to Elm Grove.
The developer clear-cut 92 acres and slanted drainage toward Elm Grove.
No detention ponds, silt fences, berms, sand bags, or filter socks had been installed to retain water that I could see. Also, with the exception of one or two small groves of trees, no vegetation remained to slow or absorb runoff.
The developer covered up an existing stream/ditch according to residents.
Near the end of a long, severely eroded drainage ditch, the developer installed a box culvert that couldn’t handle the volume from this storm. It backed water up and flooded the site according to residents.
The overflow then went into Elm Grove.
According to residents, construction employees routinely access the site from Elm Grove streets. Their trucks created ruts that channeled water into the streets.
Because the storm drain capacity could not keep up with the rainfall rate and the water flowing from the development, water rose in the streets and flooded homes. Most people I talked to had 12-18 inches of water in their homes.

The Difference? The New Development

Storms as intense as Tuesday’s have happened before without flooding in Elm Grove. Heck, not even Harvey flooded the area. No blockage existed in the sewer or the existing drainage ditches in Elm Grove. Clearly, the one thing that’s different in this equation is the new development.

Arrow represents direction of drainage in the clearcut area. Developer funneled water toward the L-shaped ditch. However, the water started flowing through streets and homes instead. Worst damage was in oval which is approximate in size and shape. Not all homes in oval flooded.

*No blockages downstream in ditch. So ditch blockage was ruled out as contributing factor.*

Drone Stills from Jim Zura

*Drainage on site seems to funnel water toward Elm Grove and then down toward the culvert shown below.* *However, it appears that rain overwhelmed the drainage capacity and the lack of vegetation accelerated runoff.*

If dirt piled along tree line was supposed to represent a berm, it certainly wasn’t continuous. Water flowed through openings according to residents, for instance, where men are standing in lower left.

*Looking West toward K-Park HS. Elm Grove is out of frame on the left. Note how pools of water are larger on the left than right indicating that runoff is flowing towards Elm Grove.*

View from the Ground

*Shot taken on 5/7/19 from Woodland Hills Drive in front of Kingwood Park High School, looking southeast toward Sherwood Trails.*

*Sewers had not yet been installed as of 5/7/19.*

*On 5/7/19, the entire site was a mass of muck.*

*A drainage ditch or linear pond in-the-making shows signs of severe erosion. This ditch carried water toward the homes in Elm Grove that flooded.*

*Wider shot of same area. Not a blade of grass in sight. Rivers of mud everywhere.*

Life Disrupted

*Contractors were swarming the neighborhood one day after the flood.*

*Home after home. Street after street. Shattered lives. Few people in this neighborhood had flood insurance because it had never flooded.*

The transition between Village Springs Drive in Elm Grove and the new development in Montgomery County. You can tell from the mud in the streets where the water came from. Residents report water rising in the street before it rose in the drainage ditch that bisects the neighborhood.

Family Closest to the Problem

*Abel Vera, homeowner on Village Springs Drive, adjacent to the new development.* *The following pictures are from his home and used with his permission.* *His beautiful pool is filled with muddy flood water.* *The heavy stone pots and patio furniture were lifted by the flood and slammed into the fence.*

*Vera’s back fence shows how high the water reached in his yard.*

*The “upstream” side of Vera’s car, parked in his driveway during the flood. The wheel was facing the new development.*

*Vera points to the waterline on his kitchen cabinets. He spent five hours vacuuming water from the recessed hardwood floor in his kitchen.*

*Newly installed hardwood floors will need to be replaced.*

*Culvert at the end of the ditch reportedly backed water up. Water then moved toward upper right, the Vera home.*

Within the next day or two, I hope to edit the drone footage with the talented Jim Zura who shot it. As I post this, I hear thunder outside from yet another round of storms. And I’m praying for the people of Elm Grove.

Posted by Bob Rehak on 5/9/19

618 Days since Hurricane Harvey