New Kings River Development Drainage Analysis, Plans Raise Questions

Harris County Engineering has released preliminary drainage plans and a drainage analysis in response to a FOIA Request for a new Kings River Development located along Kings Park Way and Pinehurst Trail Drive. The drainage analysis claims “no adverse impact” on surrounding neighborhoods because of the three detention ponds they plan to build.

But the analysis by R.G. Miller Engineers, which is now under review by Harris County Engineering:

Omits data
Contains misstatements
Leaves out related reports
Includes alarming assumptions.

Together, these issues call into question the conclusion of no adverse impact.

In the meantime, the clearing of the Phase-1 site, owned by Meritage Homes, continues, even though Harris County disapproved construction plans for its detention basin.

*Looking W.* *Mertitage Kings River Phase I construction site was about 80% cleared as of 1/29/24 at noon.*

Let’s look at each of the issues above.

Data Omitted

Typically, engineers justify “no adverse impact” by comparing pre- and post-development peak-discharge rates. If the post- rate does not exceed the pre- rate, then they claim “no adverse impact.”

But the drainage analysis does not show the pre-/post comparison in a simple table. Why?

Take Tables 7 and 8A, for instance. They address calculations involving Pond 1 on the first section of land now being cleared (see above).

*Table 7 from R.G. Miller Drainage Analysis, Page 7*. *Note blank boxes top left* *after Existing Peak Discharge.*

The data is missing. They omitted the data again in another series of tables later in the analysis.

*Drainage Analysis Table 8a*, *Page 13*. *Note missing data after “Maximum Allowable Outflow,” line 6.*

A third table (1-D, page 8) includes pre-development runoff for all three ponds. Together, they seem to justify the claim.

But I can’t find the peak runoff for Pond 1 by itself in any one of the pre/post comparisons. Keep in mind that the second two ponds won’t be built for years. In the meantime, Pond 1 will be the sole source of mitigation.

Soil Analysis and Environmental Reports Not Completed

Discharge rates also depend on soil types. That’s because the soil on a site affects the rate of infiltration.

But Section 10 on Page 15 of the drainage analysis talks about how a geotechnical report (which would determine infiltration rates) has not yet been produced. It says, “…a geotechnical investigation is required to characterize potential soil conditions.”

The drainage analysis also never mentions the wetlands on the property. Those would normally be addressed in an “Environmental Issues” section. But that section says only, “Environmental investigation has not been completed in this study.”

This is kind of like your jet taking off without a full load of fuel. You might get to your destination, but…

Misstatement?

The report also contains a huge misstatement.

For instance, Section 2.2.3 (Results) begins with, “The detention storage volume required for the proposed 41.5 acres residential development is 26.98 acre-feet per acre.” That would mean they require 11,196.7 acre-feet of detention. But they’re providing only 39.8 acre-feet of storage volume.

I’m sure this is a typo. Another section of the analysis later states that the 26.98 figure is computed by using Harris County’s minimum requirement of .65 acre-feet per acre.

Such misstatements and poor proofing call into question other calculations in the analysis.

Alarming Assumption

Section 2.1 (Existing Conditions) states, “Since the proposed detention ponds outfall to an existing 30-in RCP and 36-inch RCP at Pinehurst Trail Drive, the maximum allowable discharge in this study will be the maximum capacity of the 30-inch RCP and 36-inch RCP.”

That sounds to me as though they feel they can use 100% of the existing storm sewer capacity…without regard to the needs of surrounding neighborhoods. For instance, assume that surrounding neighborhoods already use 75% of existing capacity. If the new development uses 100%, that means the drains would be 75% over capacity.

No Clear Support for Claim of “No Adverse Impact”

Although, they claim “no adverse impact,” it’s not clear to a lay person how they arrived at that assumption.

In fairness this report is still under review by Harris County Engineering.

The development also sits in the City of Houston’s extra territorial jurisdiction.

I hope both entities make the engineers clarify the basis for their claims and produce a final report that the public can understand. I stared at these 47 pages all day and still don’t understand how they can justify “No adverse impacts.”

Is it too much to ask for clarity when the safety of people and their homes is at stake?

Construction Plan of Detention Basins “Disapproved”

Evidently Harris County Engineering had some concerns with this development, too.

On 2/9/24, Engineering disapproved the R.G. Miller construction plans for Detention Basin #1. Engineering kicked the plans back for housekeeping-type issues.

For instance, the plans didn’t contain:

ID of the channel the ponds drained into
A Project name
A Project number
The signature and seal of a registered Texas professional engineer (PE).

Harris County used to refuse to review plans that weren’t signed and sealed by a PE. I am told that such gratuitous omissions make reviewers angry.

I would link to all the construction plans here. But the file sizes are massive and the construction plans moot for now. More later when/if they’re approved. For now, to review the entire 45-page, 16 meg drainage analysis, click here .

Posted by Bob Rehak on 2/26/24

2372 Days since Hurricane Harvey

The thoughts expressed in this post represent opinions on matters of public concern and safety. They are protected by the First Amendment of the US Constitution and the Anti-SLAPP Statute of the Great State of Texas.