Tag Archive for: City of Houston

Woodridge Village Still Silting Up Taylor Gully

Despite countermeasures, such as silt fences and rock baskets designed to catch erosion, Woodridge Village is still silting up Taylor Gully. And this comes shortly after Harris County Flood Control just cleaned out the ditch to restore its conveyance.

Nicole Black-Rudolph captured these two photos downstream from Woodridge. They show the water in Taylor Gully at the Turtle Bridge in Woodstream. The first shows what the water normally looks like. The second shows what it looks like now.

Normal/Now Photos by Nicole Black-Rudolph showing increased silt in Taylor Gully.

Where Did Silt-Laden Water Come From?

Following Taylor Gully upstream, you come to 268 clear-cut acres – Perry Homes’ Woodridge Village. All pictures below show Woodridge Village on the morning of September 7, 2020. A nearby Elm Grove resident, Jeff Miller, reported .7 inches of rain fell in his gauge on 9/5 and 9/6. That wasn’t enough to cause flooding, but it was certainly enough to erode sediment as the pictures below show.

Looking SSW across Woodridge from the top of the N3 detention pond on the eastern border. Elm Grove is at top. Everything slopes toward Taylor Gully in the upper left.
Woodridge Village, looking NW from over Taylor Gully
Looking north at N3 detention pond day after rainfall. Silty water is still flowing out of the pond.
Looking east at the concrete lined portion of Taylor Gully on the Woodridge site where water exits the site and crosses into the open channel on the Harris County side of the county line, out of frame to the right (see below).
Looking south at Taylor Gully immediately south of the county line. Note how color of water in ditch matches the color of water on the right in the side-by-side comparison photo above.

Political Ping Pong

Perry Homes’ troubled development in Montgomery County has been caught in a political ping-pong match that has delayed either its ultimate build out or conversion into a regional detention facility. The match started in February when the City of Houston said Harris County should pay for the conversion. It has continued until now. Harris County Precinct One Commissioner Rodney Ellis keeps heaping one new condition after another on the sale of the property to Harris County Flood Control District.

Woodridge contributed to flooding Elm Grove Village in Kingwood (immediately to the south and across the Harris County line) twice last year. Perry contractors had clear cut 268 acres and filled in natural streams and wetlands that criss-crossed the property before fully installing detention ponds. When major rains stuck on May 7th and September 19th last year, sheet flow from Woodridge, coupled with water backing up in the streets of Elm Grove, flooded hundreds of homes. The area is still recovering.

Harris County Flood Control immediately started a project to restore the conveyance of the ditch which was badly silted, in part due to construction activities.

Now, despite best efforts to reduce erosion with conventional countermeasures, the exposed surface washes downstream with each rain. This re-deposits more sediment, which the Flood Control District just removed. (See two photos below from 2019.)

Taylor Gully Before 2019 Clean out.
Taylor Gully After 2019 Clean Out

Pray there’s movement on this deal soon. Perry Homes should plant grass on their property until the ping-pong match is over. Silt fences and rock baskets alone just don’t do the job.

Posted by Bob Rehak on 9/8/2020 with photos from Nicole Black-Rudolph and Rain Data from Jeff Miller

1106 Days since Hurricane Harvey and 355 since Imelda

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.

City of Houston Map Shows Extent of Water Flood Hazards for Many Smaller Ditches, Streams

If you fear flooding from a small stream and you live inside the Houston City limits, this is THE resource for you. It’s the City’s Water Flood Hazards Viewer. And it’s incredibly detailed. It even shows the extent of flood hazards around many unnamed temporary streams and man-made ditches.

Water/Flood Hazards within the City of Houston

The image above shows Ben’s Branch where it cuts across the Harris/Montgomery County Line. Many homes and businesses in this area flooded during Harvey and Imelda despite being three miles from the nearest river.

The different shadings and cross-hatchings represent floodways, 100-year and 500-year floodplains. I checked around neighborhoods near me where I was familiar with the extent of flooding. The map seems to be very accurate. I only found one or two properties that I would have reclassified.

Impressive Gallery of Base Maps and Other Features

The City’s Water Flood Hazards site contains an impressive gallery of 25 different base map options. They range from customary street maps and satellite views to topographic maps and more.

You can also measure distance and direction with the built in tools. And unlike many such maps, this one contains built in drawing tools that let you make notations and share them with your friends or associates.

Of course, it includes information on flood zones near major rivers, too. It even includes information on hurricane evacuation zones near the coast.

You can see the outlines of Harris County in the extent of the waterways. The bright areas near the coast represent hurricane evacuation zones and zip codes.

Incredible Flexibility

Because the system is built on a geographic information system database, you can even add data from other databases. That makes the map reflect additional types of information. But warning: this can get very technical.

Great Tool for Research

If you’re considering buying a property or flood insurance, and you live in the City or Harris County, this is definitely a map you should bookmark. The Water Flood Hazards Map is an incredible research tool. For ease of future reference, I have listed the map on the Links page of this website under Floodplain Maps and Elevation.

Posted by Bob Rehak on 9/6/2020

1104 Days after Hurricane Harvey

Tetra Tech Study Provides Clues To Possible Mouth Bar Dredging Strategies

FEMA has agreed to dredge another million cubic yards from the the area near the San Jacinto West Fork Mouth Bar. A report produced for the City of Houston by Tetra Tech helped convince FEMA. The report relied on sonar, LIDAR, and core sample data to estimate the total volume of sand deposited by Hurricane Harvey in that area: approximately 1.4 million cubic yards.

Need for Ruthless Efficiency

While another million cubic yards may sound like a lot, the area is huge. Dredging the whole 4.3 million square yard area would add only about 8 inches of water depth and leave an underwater mesa between the West Fork and the Lake. According to local geologists Tim Garfield and RD Kissling, who have studied the problem extensively, that would create a sediment trap that accelerates accumulation of sand from future storms.

So, what to do?

Three Strategies Discussed to Date

Those close to the project have discussed several strategies to date.

  • The Corps’ initial strategy: Dredge upstream from the mouth bar. They said 1D modeling showed that would accelerate water flowing into mouth bar and give it the velocity needed to push sand from the mouth bar farther out into the lake.
  • Another strategy: dredge downstream from the mouth bar and let the river push the mouth bar into the dredged area.
  • A third strategy: reconnect the river and the lake with a narrow channel that accelerated the flow of water and carried suspended sediment out into the broader lake south of the 1960 bridge.

2019 Tetra Tech Report

Stephen Costello, the City’s flood czar, says that new survey and modeling work has yet to be completed. That will ultimately determine where new dredging happens. However, he also added that consulting Tetra Tech’s exhibits would help provide clues as to where dredging might be most effective, based on knowledge accumulated to date.

The first chart in Appendix A showed the coring locations and transects (survey lines) of the lake’s bottom profile.
The second chart shows what they found in various coring locations. The feet indicate the thickness of the top layer.

Composition of the core samples provides clues as to what was laid down when. Sand (the yellow dots) is generally laid down during floods which have the energy to transport the heavy particles. However, clay and silt (the green and blue dots) are smaller. So they tend to drop out of suspension when water is calmer.

Finding sand above silt in a core sample indicates that a storm like Harvey likely laid down the sand.

The third chart is the most crucial. It’s a difference map that shows areas of deposition and scour pre- and post-Harvey. This shows two things: where most sediment fell out of suspension and where the main flow of the river tried to churn a path through the mounting muck.

From the difference map above, you can see that the river tried to scour its way through the sediment along a path from LH-16 to LH-21 to LH-23. You can see another area of scour to the far right from LH-15 to LH-25 to LH-26.

Where River Flowed Before Lake Was Impounded

Interestingly, the area of scour to the left follows the river’s relic channel.

San Jacinto River map before Lake Houston was impounded

Note how the West Fork hugged what is now Atascocita Point – the thumb of high land that sticks up in the Tetra Tech illustrations.

Harnessing Natural Energy of the River

From the third and fourth illustrations above, one might conclude that excavating a channel near Atascocita Point represents the best way to harness the natural energy of the river. That’s the shortest channel where scour is deepest.

Given the million cubic yard limit, that path also represents a chance to dig the deepest, widest channel possible within the budget. When technicians compiled the difference map above, most of that path was already at or below its 2011 level.

500,000 square-yard path outlined in yellow would let dredgers excavate six feet. Average bottom depth is already 5.5 feet in that area.

Following that path also lets you funnel future sediment through the FM1960 causeway and disperse it out into the wider, deeper lake.

Next Steps and Timing

At this point, we don’t know what Imelda did to this area. Imelda struck shortly after the Army Corps completed its post-dredging survey in this area last year.

Before the additional dredging can begin, several things must happen.

  • Completion of a new survey
  • Model different scenarios
  • Identify best strategy
  • Locate suitable placement area
  • Compile scope of work
  • Bid job
  • Mobilize

Based on past experience, that could take months to a year or more. It took 13 months after Harvey for the Corps to put equipment in the water for its Emergency West Fork Dredging Project. However, we don’t have as many unknowns this time.

Posted by Bob Rehak on 9/5/2020

1103 Days since Hurricane Harvey

How Much Will Dredging Another Million Cubic Yards Reduce the West Fork Mouth Bar Area?

Earlier this month, the City of Houston announced that FEMA would pay to dredge another million cubic yards of sediment from the West Fork Mouth Bar. What does that mean in practical terms? What are the objectives of the program? How wide and deep will they go? Neither the objectives, nor a dredging plan, have yet been released.

The official plan will hopefully rely on new survey work and hydraulic modeling. A survey boat has been seen on the lake for several weeks now.

Since January of this year, the City of Houston has been trying to reduce the above water portion of the mouth bar with mechanical dredging, a much slower process than hydraulic dredging. Note how shallow the water is in the foreground.

How to Play Armchair Engineer

In the meantime, since fall football is in doubt due to COVID, here’s a simple way to keep your armchair quarterbacking skills finely honed. What would you do if you were the project engineer or manager? Play what if and experiment with different scenarios.

  • Download and open Google Earth Pro. It’s free.
  • Zoom in on the West Fork Mouth Bar.
  • Select the measuring tool.
  • Click on the polygon tab.
  • Select square yards for the unit measurement for the areas you will define.
  • Now start second guessing the project engineers. Play “what if” by defining an area that you would like to see dredged.
  • Readjust the points that define the area by dragging them in, out, up or down.
  • Watch the total square yards recalculate as you move the points.

Examples of Different Scenarios

Here are some examples to show you what I’m talking about.

4.3 Million Square Yard Area, Roughly 8 inches Deep
Largest area. This scenario takes in everything between where the Corps stopped dredging in its Emergency West Fork Program and the FM1960 Bridge.

The scenario above takes in the mouth of Ben’s Branch, plus all the other drainage ditches that empty Fosters Mill, Kings Point, and Atascocita north of the FM1960 Bridge.

Here are the ditches highlighted in blue. Source: Harris County Flood Control District Flood Education Mapping Tool.https://www.harriscountyfemt.org

The scenario above covers 4.3 million square yards. But with a budget to dredge only 1 million cubic yards, you would divide 1/4.3 = 0.23 yards of depth. That’s less than a third of a yard. It works out to about 8 inches.

3 Million Square Yard Area, 1 Foot Deep
In the next scenario, I pulled the boundaries in so that the area equaled 3 million square yards.

This scenario is a little more intuitive. You’re dredging 1 million cubic yards across an area of 3 million square yards. Within this bounding box, you could reduce the level of sediment roughly a foot.

2 Million Square Yard Area, 18 inches Deep
If you reduced the area to be dredged to 2 million square yards, you could reduce the level of sediment by half a yard or 18 inches.
1 Million Square Yards, 3 Feet Deep
Path followed by the relict channel before Lake Houston was built.

If you reduced the area further, to 1 million square yards, you could dredge to 3 feet. With the five feet of depth already there, you could have an eight foot channel connecting the river and the lake. Make it narrower and you could even go deeper. And perhaps, just perhaps, keep sediment from accumulating so rapidly upstream of the FM1960 bridge.

Difficult Choices Ahead

As you can see, engineers have some difficult choices ahead. They must chose between unblocking channels and streams, or dredging a channel roughly the size of the upstream west fork all the way to the 1960 bridge.

Last year, the Corps reduced the 600-acre area between the mouth bar and Atascocita Point to an average depth of 5.5 feet. So we have a good head start. But there are other considerations:

The West Fork was roughly 22 feet deep where the Corps stopped dredging just west of the mouth bar. Because of scouring, it’s at least that deep where the west fork passes under FM1960.

As a result, water coming down the west fork hits an underwater mesa that still blocks off three quarters of the conveyance.

Prominent area geologists, such as Tim Garfield and RD Kissling, theorize that that wall traps sediment and is rapidly diminishing the value of previous dredging programs. They believe that the most important objective for this phase of dredging should be to “reconnect the West Fork with the Lake.”

But Advancing Delta Now Blocks Major Streams, Channels

Meanwhile, consider this, too. In 2014, Bens Branch and the drainage ditch that empties large parts of Fosters Mill and Kings Point had a clear path to the river. Today, both are blocked by the mouth bar and an advancing delta within the lake. Compare the two images below.

Google Earth view from 2014 shows steams could still easily connect with relict channel.
Today, however, an advancing delta within the lake blocks them.

These are some of the real world trade offs that engineers and project managers must deal with every day.

So to return to the football analogy, do you send your receivers wide or deep? Do you have them hug the sidelines or cut for the goal post?

Understand that this isn’t a game, however. It’s a struggle to return a community to prosperity.

What would you do? And why?

Posted by Bob Rehak on 8/31/2020

1098 Days since Hurricane Harvey

New Flood-Map Timetable and How It Affects New Development

Because of low interest rates, new developments seem to pop up weekly around the Lake Houston Area. The question often arises, “How will the development of new flood maps affect the development of new subdivisions?” Most people by now have heard that City building code revisions now require elevation at least two feet above the .02-percent-annual-chance flood (formerly known as 500-year flood). But does that mean two feet above the old floodplain or the new? Due to a little-known provision in the City’s floodplain regulations, it means the new floodplain even though the new floodplain maps are not official yet.

Developments in various stages in the northeast Houston Area and the City’s ETJ (extra territorial jurisdiction). From City of Houston Plat Tracker Plus.

Timetable for Updating Flood Maps

Here’s what you need to know if you’re concerned that someone may be building future buyouts next to your neighborhood. First the timetable for new flood maps.

Remaining timetable for new Harris County Flood Maps

Even though FEMA won’t release the new flood maps officially for approximately another five years, developers should still be building to the higher standards associated with newly acquired data (in other words, the data on which the new maps are being built). See below.

Floodplain Regs Authorize City Engineer to Use Data Behind New Flood Maps

Section 19-4 of the City’s Floodplain regulations address Use of other flood hazard data to supplement the effective Flood Insurance Rate Map (FIRM). It states, “New elevation and flooding studies are undertaken by or under the auspices of FEMA and local political subdivisions, such as the Harris County Flood Control District. Upon determination that the data generated by such a study appears to be reliable and based upon sound engineering and surveying practices and further that the study’s data indicate that the effective FIRMs are FIRM is materially inaccurate, the city engineer may cause the study data to be administered for purposes of this chapter as though it were a part of the effective FIRM. Any such determination shall be issued in writing and a copy shall be placed on file in the office of the city secretary. The city engineer is authorized to utilize updated information from FIS and floodplain models in administering this chapter.”

Basically, that means even though the new maps have not yet been adopted, the City Engineer can require developers’ plans to reflect the new underlying data as though it were part of the current map. In this case, the new underlying data is already in hand.

MaapNext Website Describes New Data Improvements

Current floodplain maps will change greatly according to Harris County Flood Control. The district has already started releasing information on a new website called MaapNext (Modeling, Assessment and Awareness Project).

Components of the MaapNext program. A $3.5 million FEMA grant made MaapNext possible.

According to the MaapNext site, we now have updated data based on:

  • County-wide impervious data developed from 2018 aerial imagery
  • Completed flood risk reduction projects
  • NOAA’s recently-released Atlas 14
  • Updated terrain data

We also have new and better ways to model that data since the last survey after TS Allison:

  • 2-Dimensional Hydraulic Modeling
  • New hydrology method that better accounts for a watershed’s conveyance capacity
  • Rain-on-Grid analysis that identifies previously unmapped urban flood risk.

And, we are beginning to develop better maps:

  • Modeling results in GIS (Geographic Information Systems)
  • New flood-risk data sets describe results in a variety of useful ways

Reportedly, the City is already requiring developers to act on the new “best available data” instead of waiting five years for the next maps.

Chapter 19 of the City Ordinances deals with dozens of other requirements for building in floodplains. But more on those in future posts.

Posted by Bob Rehak on 8/29/2020

1096 Days (Three Years) 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.

Lake Houston Level Now Being Lowered in Advance of Hurricane Laura

Mayor Pro Tem Dave Martin announced at 4:31 p.m. Tuesday that Houston Public Works will initiate the temporary lowering of Lake Houston within the hour. The City made this decision after taking into account the fast-changing nature of Hurricane Laura. The Coastal Water Authority will lower Lake Houston to 41.0 ft from 41.59, another six tenths of a foot, which is 18 inches below full pool.

Laura should arrive late tomorrow or early Thursday as a Category 3 storm. Hurricane conditions are expected in Chambers and Liberty County – with 45-60 mph winds east of I-45 throughout the Lake Houston Area.

Floodgates on Lake Houston Dam photographed on 6/16/2020.

2 to 4 Inches Expected

The National Hurricane Center predicts that Hurricane Laura will bring 2 – 4 inches of rain to the Lake Houston Area in the next few days. Isolated areas could receive 6 inches. These rainfall amounts exceed the 3 inch trigger to lower Lake Houston, said Martin. 

Lake to Be Lowered Another 7.2 inches

As a result of these predicted rainfall amounts in addition to the rainfall that will be accumulated to our east, the Lake will be lowered gradually overnight from the current level, which is 41.6 ft down to an elevation of 41.0 ft. Six tenths of a foot is 7.2 inches.

The Lake will be maintained at a level of approximately 41.0 ft while there is an immediate inclement weather threat. Once that weather has moved out of our area, the Lake will be allowed to naturally refill from the storm’s runoff.

Some fluctuations in Lake level can be attributed to high winds so please keep that in mind when checking Lake levels.

Secure Shoreline Property NOW If You Have Not Already

Property owners were given notice Friday afternoon to secure property along the shoreline for a potential temporary lowering of Lake Houston. If you have not already done so now is the time to take action to secure your shoreline property.

Dave Martin, Mayor Pro Tem

The lake will be lowered at a cautious rate so as to not impact those living downstream. At the completion of this temporary lowering effort the total reduction in the level of Lake Houston from normal pool of 42.5 ft to 41.0 ft will be 1.5 feet. 

For More Information

Residents may monitor the lowering of Lake Houston by visiting the Coastal Water Authority website or visiting Mayor Pro Tem Martin’s Facebook page for updates from the District E office.

No Mention of SJRA

Martin’s press release made no mention of the SJRA or Lake Conroe. Lake Conroe, which is farther west should receive less rain than Lake Houston from Laura.

Posted by Bob Rehak on 8/25/2020 at 6 pm, based on a press release from Houston Mayor Pro Tem Dave Martin.

1092 Days after Hurricane Harvey

Laura Intensifying into Major Hurricane; Prepare for Big Winds, Power Outages

These warnings were just issued by Jeff Lindner, Harris County Meteorologist, the National Hurricane Center, and City of Houston:

Hurricane warnings issued from San Luis Pass into Louisiana.

Landfall of a devastating hurricane likely between Galveston Bay and Sabine Pass tomorrow night.

Rush to complete preparations to protect life and property.

Heed all evacuation recommendations.

Discussion

Laura – now a hurricane with sustained winds of 75mph – is continuing to intensify. The hurricane will likely rapidly intensify over the next 24-36 hours, right up to landfall along the upper TX coast. The National Hurricane Center predicts Laura will become a major hurricane with sustained winds over 110 mph by tomorrow night or early Thursday morning when it makes landfall somewhere between Galveston Bay and Sabine Pass.

Track: 

Everyone should be planning for the landfall of a very serious hurricane between Galveston Bay and Sabine Pass on the Louisiana border. Additional shifts in the track are possible that could bring the core of Laura into Galveston Bay and Harris/Galveston Counties.

The large wind field will result in strong winds likely 100-150 miles inland across east Texas.

Prepare for power outages extending well inland along with significant wind damage and extended outages.  

Intensity:

Prepare for the impact of a major hurricane (cat 3 or higher). Once the inner core of Laura forms, significant intensification is likely, and conditions look very favorable for intensification. 

Tropical Storm force winds will begin along the coast at around 8:00 pm Wednesday evening.

Advice from City, Lake Status

“Rainfall amounts in the Lake Houston Watershed over the next six days are expected to be 2 – 4 inches with isolated accumulation of 6 inches possible,” said Dave Martin. “Currently, the Lake Houston Watershed is dry and the projected impact to our area will be to our east with the largest possible impact expected along the East Fork of the San Jacinto River. Lake Houston is already down one foot from normal pool with the possibility of being lowered additionally, if necessary. Please make sure all property along the shoreline is secured in the event additional lowering is ordered.”

“Regardless of where this storm lands,” said Martin, “it is important all residents prepare themselves and have a plan. Hurricane Laura will likely be similar to Ike with severe wind impacts and power outages. The City of Houston has prepared resources to help you get ready for upcoming disasters and make sure you are prepared for this one. Please visit www.readyhoustontx.gov to learn more.

Actions

  • Prepare for the landfall of a major hurricane along the SE TX coast
  • Bring in anything in your yard, such as lawn furniture, that could become airborne.
  • All preparations will be to be competed by 6:00 p.m. Wednesday evening.
  • Heed all evacuation orders. 

For hurricane preparation tips from the National Weather Service, click here.

Posted by Bob Rehak on 8/24/2020 based on input from the National Hurricane Center and Jeff Lindner, Harris County Meteorologist.

1091 Days after Hurricane Harvey

Developer Seeks City Approval to Expand Commons of Lake Houston into Floodplain – Without Detention Ponds

Clarification: General plans, as described below, are primarily about street layouts. However, many people have been trying to raise awareness at the Planning Commission that street patterns are affected to a significant degree by the volume and and layout of drainage and detention features. And, of course with Atlas 14 that is more true than ever. Danny Signorelli, CEO of the Signorelli Companies, took issue with this post. I offered him an opportunity to print a rebuttal verbatim. He refused the offer.

Signorelli Companies have filed a general plan with City of Houston Planning Commission for a new development on the San Jacinto East Fork. It’s called “Crossing at the Commons of Lake Houston.”

Second Time Around for Developer

According to residents in other parts of the Commons, Signorelli tried to develop this property before and reportedly wanted to add 4-6 feet of fill to the floodplain. It’s not yet clear what they have in mind for this iteration of the project. However, comparing the general plan to FEMA’s National Flood Hazard Layer Viewer shows that parts of the development are still in the flood plain. (See below.)

No Detention Ponds Shown on Plans

The general plan filed with the planning commission also shows that the developer shows no plans for detention ponds on the property. A best practice to reduce flooding is to “retain your rain.”

General plan filed with the City of Houston Planning Commission shows no detention ponds. For a large, high res PDF, click here.

Location

Here are satellite and close-up views of where the new subdivision would be relative to the the surrounding area and existing parts of the development.

Crossing At the Commons of Lake Houston is in the Huffman area opposite Lake Houston Park and East End Park on the west side of the East Fork.
Crossing at the Commons of Lake Houston relative to existing streets in the Commons. From General Plan inset.

Floodplain Issues

Parts of the proposed development will be in the floodplain. And those floodplains will soon expand to include even more homes. See the two dotted lines below.

Close up of PDF above shows how 100-year floodplain (dotted line on left) and 500-year (dotted line on right) would impact proposed homesites. Note the drainage easement in the lower left.
FEMA’s National Flood Hazard Layer Viewer shows parts of the proposed new 75.3-acre subdivision would be in the 100- and 500-year floodplain.

Ironically, just last night, the City of Houston and its partners (Harris County Flood Control, Montgomery County and the SJRA) presented a draft of the findings of the San Jacinto River Master Drainage Plan. In it, they recommended avoiding flood plain development to keep people out of harm’s way. See slide below from their presentation.

Slide from San Jacinto River Master Drainage Plan Draft Report shows how adding fill to flood plains can affect other homes in area.

The presenter also discussed how the floodplains were expanding due to revisions of flood maps based on new hydraulic and hydrologic modeling not yet been shared with FEMA.

The 100-year floodplain in many areas will likely expand well into the 500. And the 500-year flood plain will likely expand into areas previously not shown in ANY floodplain.

San Jacinto River Master Drainage Plan Draft Report 8/13/2020

Thus, the number of homes affected by floods could greatly expand beyond the number shown above.

Drainage in Commons Already a Problem

Plans also show that homes will be built very close to a drainage easement. Yet existing ditches in the Commons are eroding badly due to lack of maintenance. Below is a picture of one taken in January last year. Residents say the trees are still there and the erosion became much worse during floods in May and Imelda.

Commons drainage ditch photographed last year.

Less Than One Fourth of Property Now Under Consideration

The tract is 332 acres, but only 75.3 is proposed for development at this time.  It is entirely located within the incorporated limits of the City of Houston. The entire tract is adjacent to COH flooding easements for Lake Houston. 

How to Voice Concerns, If You Have Them

Here’s how you can voice concerns, if you have them. The City Planning Commission will hold virtual meetings until further notice. So it’s very easy to make public comments. You can sign up to speak by going to the Planning Commission Home Page.

The next Planning Commission meeting is Thursday, August 20, 2020. If you’d like to speak, you must sign up at least 24 hours before the meeting.

Use the online speaker form at https://www.tfaforms.com/4816241 or submit comments on an item via email to speakercomments.pc@houstontx.gov.

Speakers have only TWO MINUTES. Key points to consider:

  • Floodplain will officially be expanding soon.
  • Some of these homes are already in it.
  • Many more soon will be.
  • That could require fill.
  • And fill will make flooding worse for other homes near the river on both sides.
  • No detention ponds or drainage plans are shown.
  • The Planning Commission should consider these things.

Posted by Bob Rehak on 8/14/2020

1081 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.

San Jacinto River Watershed Virtual Meeting Tonight Will Unveil Specific Recommendations to Reduce Flooding

I can’t urge you enough to watch the San Jacinto Watershed Master Drainage Plan Meeting tonight at 6:30.

Flooded Street by Julie Yandell. During Harvey.
Flooded Street during Harvey. Photo by Julie Yandell.

Updating of River Models Leads to New Insights

I previewed the presentation this morning and was extremely impressed. The study partners have updated or created hydraulic and hydrologic models for 535 miles of major streams in the river basin. They’ve also integrated the models and accounted for new developments across 3000 square miles in seven counties.

As a result, we now have a much better understanding of:

  • Where water comes from
  • Which areas have the highest potential for flooding
  • Where large regional detention basins can be placed to reduce flooding.
  • Other strategies to reduce flooding.

New Flood Maps, Sedimentation, Better Warning Systems

You don’t want to hear about this stuff second hand. The presentation also includes discussions of:

  • How much flood plains have really expanded compared to current FEMA maps.
  • Sedimentation and strategies to reduce it
  • Improving flood warning systems

If you’re flooded, or are concerned that you might, don’t miss this. This study will be the cornerstone of grants applications to mitigate flooding in the region.

Cornerstone of Lake Houston Area Mitigation Efforts

Two years ago, before the flood bond vote, community opinion coalesced around a three-part solution to flooding in the Lake Houston Area.

  • Reduce/delay the input by increasing upstream detention
  • Increase the throughput by dredging blockages
  • Speed up the output with additional gates on the Lake Houston Dam.

Tonight, you will get a chance ask questions of the people who have been studying those options and others for 18 months. Here’s how to log in:

Thursday, August 13, 2020

6:30 p.m. to 7:30 p.m. 

Join online at PublicInput.com/SanJacMasterPlan

Or by phone at 855-925-2801 with Meeting Code: 9742 

Order the pizza now.

This study is a cooperative venture of FEMA, Harris County Flood Control, SJRA, City of Houston and Montgomery County.

Posted by Bob Rehak on August 13, 2020

1080 Days after Hurricane Harvey

Long-Term Lake Houston Dredging Plan in Development; West Fork Mouth-Bar 60 Percent Completed

In January, the City hired DRC Emergency Services, LLC (DRC) to begin mechanical dredging of the San Jacinto West Fork Mouth Bar. I’ve provided periodic updates on that. According to Houston Mayor Pro Tem Dave Martin, DRC has now officially completed 60% of that project.

In the meantime, other related dredging projects, including East Fork dredging and long-term Lake Houston maintenance dredging are reportedly taking shape. Here’s how pieces of the puzzle fit together. But one piece is still missing – long-term funding to pay for the maintenance dredging.

Two-Phase Program

DRC’s scope of work has two distinct phases:

  1. Phase One will remove accumulated materials near and at the mouth bar on the West Fork of the San Jacinto River.
  2. Phase Two will remove accumulated materials in the East Fork of the San Jacinto River AND other locations in Lake Houston.
West Fork Mouth Bar as of late June 2020.

During Phase One, 400,000 cubic yards of material will be removed over twelve months. To date, DRC has removed approximately 240,080 cubic yards of material. (See photo above.) That’s 60% in approximately 60% of the allotted time, so that part of the project is on schedule.

East Fork Mouth Bar as of May 2020. This areas went from 18 to 3 feet deep during Imelda, according to boater Josh Alberson. The above-water portion of this sand bar has grown three quarters of a mile since Harvey.

Phase Two of the project will consist of:

  • Hydrographic surveys of the West Fork of the San Jacinto River, the East Fork of the San Jacinto River, and Lake Houston to determine dredge material volumes
  • City of Houston advertising and awarding a dredging contract to the lowest responsive bidder

Phase Two will run simultaneously with Phase One to expedite dredging. 

Dave Martin, Houston Mayor Pro Tem

Mayor Pro Tem Martin did not provide an update on where Phase Two currently stands. But residents have reported seeing survey boats on Lake Houston, and the East and West Forks of the San Jacinto.

Mouth bar forming at Rogers Gully on Lake Houston. Example of kind of projects being considered for Phase 2. Photo late June, 2020.

Long-Term Dredging Plan in Development

Additionally, during Phase Two, City of Houston and its partners will develop a long-term dredging plan for Lake Houston. City of Houston or the Coastal Water Authority will execute the plan.

The intention: to fund dredging operations in perpetuity.

This phased approach will obligate the full grant funding before the 87th legislative session in 2021. This grant funding was made possible thanks to State Representative Dan Huberty (District 127) through the passage of Senate Bill 500.

Mayor Pro Tem Martin credits Huberty for his dedication to the long-term maintenance dredging activities on Lake Houston. “Representative Huberty has been a champion for his residents and a great ally in seeing these additional dredging efforts come to fruition,” said Martin.

$40 Million Project

The total project is valued at $40 million (except for the perpetuity part). Funding for the immediate dredging projects comes through a combination of:

  • City of Houston Harvey Disaster dollars provided by Governor Greg Abbott
  • Grant dollars from the Texas Water Development Board (TWDB)
  • Harris County Flood Control District (HCFCD) Bond Program.

Harris County Engineer, John Blount submitted the grant application for this project to the TWDB. But the City of Houston became a “subrecipient” and is now managing the project.

Long Term Funding – Still A Missing Piece of Puzzle

Lake Houston, a City of Houston asset, is losing capacity. Everyone has recognized that fact for decades. But as silt filled the rivers, inlets and lake, maintenance was deferred, reportedly for budgetary reasons. In 2017, during Harvey, the problem became so big that no one could ignore it anymore. Flooding was the immediate problem. But loss of water capacity is an even bigger, longer-term problem.

It’s one thing to have a long-term maintenance dredging plan and another to put it into action. But where will the money come from?

A tax on sand mines? Won’t work. Most aren’t in the City. Or even in Harris County.

Some have suggested creating a taxing district for lakefront homeowners. That won’t work either. Not enough of them. And it would create a stampede for the Oklahoma border. Moreover, it hardly seems fair; the lake is part of a City system that provides water to two million people and generates revenue.

The logical solution seems to be increasing the cost of water. Adding just a fraction of a penny per 1000 gallons should do it. Dredging isn’t just about reducing flooding. Or preserving views for lakefront homeowners. It helps preserve the lake’s capacity. And that benefits everyone.

As we develop a long-term dredging plan for the lake, we also need to consider a sustainable source of financing.

Posted by Bob Rehak on 8/12/2020 based, in part, on a release by Houston Mayor Pro Tem Dave Martin

1079 Days after Hurricane Harvey