Tag Archive for: interceptor swale

Perry Homes’ Contractors Return to Woodridge Village, But Undo Some Previous Work, Add to Sediment-Laden Runoff

After pulling all construction equipment from the Woodridge Village site in December, Perry Homes’ contractors returned this week. They are still working on the S2 (second southern) detention pond. But the new work appears to undo some previous work, and make sediment-laden runoff worse.

Woodridge Still Far Short of Promised Detention Capacity

After about 15 months of working on the Woodridge Village site, Perry Homes still has only 23% of the detention capacity installed. And even that does not yet meet Montgomery County regulations (see below). None of the work this week focused on new detention ponds that would reduce flood risk for Elm Grove residents.

Perry Homes had promised to build three ponds on the northern section. But they have not started any of those yet.

And Far Behind Schedule

On October 17th last year, an attorney for Perry Homes, J. Carey Gray, promised the Houston City attorney that Perry would have S2 completed in no more than 45 days. It has now been 86 days since Mr. Gray sent his letter and the work is still far from complete. I’m sure this creates an embarrassment to the Mayor of Houston, especially considering that Perry Homes gave $5000 to his re-election campaign. It creates the appearance of trying to buy favors.

Still Does Not Comply With MoCo Regulations

I previously detailed seven Montgomery County regulations that Perry Homes’ detention ponds did not meet. Perry Homes did not:

  • Put 30-foot wide maintenance roads around the ponds.
  • Place backslope interceptor swales around the ponds.
  • Have effective erosion control measures in place.
  • Implement protective measures for their overflow spillway.
  • Prevent increases in downstream flood levels.
  • Prepare a geotechnical report (that they shared with Montgomery County) showing groundwater levels at detention pond sites.
  • Ensure complete drainage of the detention pond.

Detention Pond Falls Short of Promised Capacity

Calculations for the capacity of the detention ponds begin from the bottom of the pond – when empty. When partially filled with water, the calculation begins from the top of the water. The bottom 2-3 feet of S2 has retained water for months, indicating that part of the pond is below the water table. So you can subtract about 20% of capacity that LJA Engineering promised and that Rebel Contractors initially built.

Adding Maintenance Road, Subtracting Backslope Swales

The flurry of work this week centered around creating the maintenance road that regulations demand. Or perhaps Perry is just building up the lip of S2 to compensate for the water it holds. Both are potentially good things.

However, workers also started filling the backslope interceptor swales they previously built. This created a sharp slope next to neighboring residents’ property and increased runoff toward the residents during last night’s rain.

Contractors placing dirt along the southern edge of the S1 pond to build a road earlier in the week.
Elm Grove Trail on left. Woodridge Village on right of silt fence. Note how land is being sloped toward Elm Grove.

An interceptor swale collects water above slopes and diverts it to the bottom of a detention pond through pipes so runoff does not create erosion on the slopes that lead to the pond.

Perry Homes has given no reason why they started filling in the swale they previously built that complied with MoCo regulations.

Looking west from Village Springs Drive. In the foreground, you can see how workers built a road and filled in the interceptor swale between it and Elm Grove on the left.
Still looking west. From this drain pipe, you can better see the grassy swale previously created to drain water into the detention pond (right) and to keep it out of Elm Grove (left).
Reverse shot, looking east. Here you can see how workers filled in the swale and created a road three to four feet high. Residents worry about the effect.
Looking east near the entrance to Taylor Gully from the road, the change in drainage toward Elm Grove (right) becomes very apparent. Picture taken Friday afternoon before rain. Road was uncompacted except for the weight of the small bulldozer spreading dirt (see first picture above).

Same Changes Between S1 and Sherwood Trails

The same changes appear along the southern edge of S1, north of Sherwood Trails, though the road does not appear as high and there also appears to be a shallow swale.

Looking west along the southern edge of Woodridge Village S1 detention pond, toward Woodland Hills from Fair Grove.

No Effective Erosion Control Yet

Perry Homes has also failed to put effective erosion control measures in place in Woodridge Village. For instance, most pond banks do not yet have grass planted on them.

The new road covered up what little grass had grown around the ponds. And raw dirt now fills the former interceptor swale.

A one-inch rain last night swept sediment into the pond, which emptied into Taylor Gully and Caney Creek before joining the East Fork of the San Jacinto.

Massive Pollution

Boater Josh Alberson took the dramatic picture below this afternoon where Caney Creek joins the East Fork. The East Fork water looks natural, but the water coming from Caney Creek via Taylor Gully is clouded with sediment. Woodridge Village is the only large source of exposed earth up Taylor Gully at this time. (Alberson verified that this sediment-laden runoff was NOT coming from the Triple PG mine up White Oak Creek.)

Water from Taylor Gully (right) merging with East Fork water (left) on Saturday afternoon, 1/11/2020, after a 1-inch rain last night.

Posted by Bob Rehak with images from Josh Alberson, Edythe Cogdill and Nancy Vera

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