I can’t urge you enough to watch the San Jacinto Watershed Master Drainage Plan Meeting tonight at 6:30.
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:
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
00adminadmin2020-08-13 16:43:272020-08-13 16:43:38San Jacinto River Watershed Virtual Meeting Tonight Will Unveil Specific Recommendations to Reduce Flooding
On 7/23/2020, consultants for the San Jacinto River Basin Master Drainage Plan gave the SJRA Board and the public a first look at a draft of the plan. The final report is due out at the end of August. The draft shows the broad outline of the team’s efforts.
Draft Shows Broad Outline of Recommendations
It shows the types of recommendations they will make. However, this draft does not yet include specific recommendations as to prioritization of projects. Those will change before the final report. For instance, much of the draft focuses on upstream detention. But specific detention site recommendations have not yet been finalized.
Funding and Partners
Below are the key slides and a brief explanation of the main point behind each. This drainage study is 75% funded by a FEMA Hazard Mitigation Grant and 25% by four local partners: the SJRA, City of Houston, Harris County Flood Control, and Montgomery County.
Scope of Study
The study area covers almost 3,000 square miles and the tributaries listed on the left.The SJRA primarily has responsibility for the portion of the watershed in Montgomery County. However, the scope of the drainage study extends to other counties including Waller, Grimes, Walker, Liberty, and San Jacinto.
Heat Map Shows Where Most Damage Occurs
The team started by looking at where flooding has occurred historically. The tan areas aboveshow where the most damage has occurred.
Goals and Methodology
The partners started by looking at vulnerabilities and identifying mitigation possibilities. Their main goals are in red. The final report will make specific recommendations for detention, buy-outs and improving conveyance. Recommendations will also improve flood warning and communication.The team started by integrating and updating all existing hydraulic and hydrologic models in the watershed as reflected on the latest 2018 lidar terrain data. They now take into account new construction, growth, additions to impervious cover, and Atlas-14 rainfall probabilities (which vary by sub-watershed within the larger watershed).To calibrate and verify its H&H models, the drainage study team examined four historical storms that, together, impacted the entire study area. They then adjusted the models using radar rainfall data, and USGS high water marks and peak flow data. The objective: to make the models reflect “ground truth.”The team is also looking at strategies to reduce sedimentation. However, this is not a major focus of this study. Their purpose is not to evaluate the relationship between sediment and flooding. Other studies will do that.
Three Main Areas of Focus
This slide shows the three major thrusts of drainage study effort over the last 1.5 years. The primary focus has been on: a) identifying the best locations for upstream detention that can reduce the volume of water coming downstream to populated areas during floods, b) where to install additional gages to improve flood predictions and warning times, and c) improving communication during emergencies.This shows the steps the drainage team went through to evaluate and rank-order potential sites for detention.
Areas of Highest Potential for Mitigation
Here’s where they found the highest and lowest potential for mitigation. The box explains the watersheds that see the most effective solutions within the SJMDP study area, as explained in the list to the left of the slide.Some drainage projects recommended in previous plans are no longer possible today because of upstream development. However, areas that once held potential for a single large project still hold potential for several smaller projects that add up to significant flood reduction.
Mitigation Project Funding
The cost all the drainage projects identified adds up to about $3 billion. They only reduce flooding of structures worth about $756 million dollars. Because costs exceed benefits, FEMA will not likely fund all of these.However, many of the projects are in areas with low to moderate income (brown and tan areas). See the large concentration in the eastern watershed. That opens up other sources of funding, such as the Department of Housing and Urban Development where the benefit/cost ratio may not be as important.
Harmonizing Regulations Throughout Region
The team will also make recommendations to harmonize floodplain development regs throughout the region. Continuing to allow unmitigated upstream development in floodplains could destroy any new investment made to protect highly populated downstream areas.
Some Problems May Only Be Solved Through Buyouts
Buyouts usually have a high benefit-to-cost ratio relative to construction projects such as detention ponds. Buyout strategies can target the most vulnerable properties, such as those in the 2- and 5-year floodplains. None of the detention projects recommended by the team will likely remove those from danger.
Steps Still Not Completed
The team has finished the steps in red. They in the process of prioritizing projects and developing a phasing plan. The last bullet point is not part of this study.
More Upstream Gages Needed to Eliminate Blind Spots
The team has also identified locations for additional upstream gages and local partners who can help maintain those gages. Think of these like a “distant early warning” system. They give river forecasters visibility into “blind spots.” Forecasters will be able to add up the rainfall on various tributaries and predict the impact and timing of flooding downstream.That could give people more time to evacuate.
Ways to Improve Communication
The team is also looking at ways to communicate better during flood emergencies. They are looking at inundation mapping, evacuation routes, and improved communication protocols.
Timetable for Remainder of Project
This chart outlines the project workflow. It shows completed steps in red, and incomplete steps in yellow.The final report with specific recommendations should be released at the end of August or in early September.
Every Little Bit Helps
I can’t wait to see this report in its final form. During the presentation, the presenter talked about reducing flooding downstream at the West Fork and I-45 by up to six feet if all upstream projects are implemented.
One thing to keep in mind: there is no single silver bullet that can solve the regions flood problems. All of these steps are additive. In my personal opinion, a foot here and a foot there can help offset future releases from Lake Conroe. People in the Lake Houston Area benefit from any and all upstream improvements.
Posted by Bob Rehak with thanks to SJRA and HCFCD
1064 Days since Hurricane Harvey and 313 since Imelda
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2020/07/Screen-Shot-2020-07-23-at-10.27.52-AM.jpg?fit=1500%2C1141&ssl=111411500adminadmin2020-07-28 16:33:252020-08-03 15:02:43San Jacinto River Master Drainage Plan Draft Provides First Look at Final Report Due Out in August
Humble ISD says the target opening date for the new transportation center is 2021. Having an additional transportation center will save an estimated $2 million in operating costs, they say, due to shorter routes and improved response times.
Transportation Centers Use Lots of Concrete
This video shows what the old bus center looks like. Lots of concrete! It is a giant parking lot. But the District does have two small detention ponds for the 29-acre site (see below).
Old Humble ISD transportation center at Will Clayton and Wilson. Note detention ponds and bottom and right of photo. Source: Google Earth.
Residents Question Whether Site Will Add to Flooding
There is some good news, however. According to USGS, there were no wetlands on this site. Nor does FloodFactor.com for FEMA show that the Transportation Center is any danger of flooding, unlike its neighbor, Woodridge Village, to the west.
New Transportation Center property is by red pin. Woodridge Village is to left, across Ford Road.Source: FloodFactor.com.
Some residents have questioned whether the new transportation center will add to their flood woes. That’s unclear. It depends on whether the District puts detention ponds on the site.
Construction Photos As of 6/16/2020
Recent construction photos below suggest that they will, but the District has not yet responded to a request for a drainage analysis and site plan. See the status of construction below. All photos taken on 6/16/2020.
The cleared space on the right is the northeastern section of Woodridge Village. The one in the upper left by the cell tower is the new Humble ISD transportation center. Looking southeast toward Lake Houston in background.Tighter shot of new transportation center shows clearing is complete. Area between cell tower and top corner looks like it could become a detention pond.Even closer shot shows them laying stormwater sewers toward back corner.Close shot of drain pipe.From the size, it looks as though they expect a lot of runoff.It also looks like they are pouring a concrete bed for the pipe.
New Ag Barn Just Blocks Away
The District’s new ag barn will also be in the same vicinity, about two blocks south – right where Ford Road turns into Mills Branch Road. During the last bond election, shortly after Harvey, the District decided to relocate the ag barn from Deer Ridge Park for the safety of students and animals.
The District has just started clearing land for that project.
The high rate of development in this area makes it imperative that everyone adheres to drainage best practices to prevent flooding. As more information about these and other projects becomes available, I will post it.
Posted by Bob Rehak on 7/2/2020
1038 Days since Hurricane Harvey and 286 since Imelda
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2020/07/20200616-RJR_4378.jpg?fit=1200%2C800&ssl=18001200adminadmin2020-07-02 08:32:562020-07-02 08:33:17Humble ISD Constructing Transportation Facility Next to Woodridge Village
Certainly, there are many honorable developers who try to build high-quality communities for people without adversely affecting downstream residents. I don’t wish to malign a whole profession. Nor do I want to fail to acknowledge the many wonderful communities they have built in this area.
But there are also some developers who put profit before people. They try to cut corners wherever they can and hope that nobody will notice. Especially regarding flood control. It’s expensive and easy because most people don’t understand it.
Grand Parkway Coming Soon To Wetlands Near You
The construction of State Highway 99, aka the Grand Parkway, has opened up vast new areas on the outskirts of Houston to developers. Many of those areas consist of wetlands and forests.
TxDoT is currently prepping land for Section H of the Grand Parkway almost all the way to FM 1960 on the east from US59.
From USGS. Wetlands near the path of Grand Parkway extension. Compare with maps above and below.
Visible Difference in Development Density Where SH99 Completed
The map below shows permit applications in the north Houston area. Compare the density of projects around sections of the Grand Parkway that have already been completed (left) with the areas on the east where the concrete has not yet reached.
This map shows permit applications in the northeast Houston area, both within the City and its ETJ (extra territorial jurisdiction. The Colony Ridge development featured below is outside the ETJ (green area) in the upper right of the map above.
Developers have even more projects underway outside the City’s ETJ (not shown on the map above).
How Development Can Affect Flooding
Kingwood residents have seen how one developer can contribute to flooding hundreds of homes. Last year, Perry Homes clearcut 268 acres north of Elm Grove before installing detention ponds. Hundreds of Elm Grove homes then flooded on May 7 and again on September 19, during Tropical Storm Imelda.
Below are recent photos of a massive 10,000 acre development in Liberty County near Plum Grove. It is about to become a 15,000 development now, thanks in part to Grand Parkway access. And yet it has only one small traditional detention pond.
Detention ponds slow down the rate of runoff to compensate for the loss of trees, wetlands and ground cover that have been replaced by streets and rooftops.
Their goal: to prevent downstream flooding.
Colony Ridge Accounts for All Growth in Liberty County In Last Decade
Colony Ridge can account for all the growth in Liberty County in the last decade. Below are some photos of Colony Ridge and its expansion near Plum Grove. The approach of SH99 will make it more accessible and therefore more attractive (at least from one point of view).
All aerial photos below were taken on 6/126/2020.
Looking north across the Grand Parkway extension toward Colony Ridge in Liberty County near Plum Grove.Just north of the Grand Parkway (upper left), you can see roads going in that will accommodate even more manufactured homes, aka trailer homes.The developer puts in roads, ditches, water and sewer. Fire hydrants? Forget it.
Developer’s Marketing Strategy
The developer tries to pass as many costs along to lot buyers as he can to maximize profit. He targets Hispanics. Residents tell me that sometimes two or three families may live in one of the homes you see here.
Nobody knows the real population of Colony Ridge because many residents are reportedly undocumented and uncounted.
Site work before parking a home is the responsibility of site buyers, many of whom openly burn brush to clear their lots. Like the developer, they’re trying to cut costs.
Land of Fire and the Forgotten
Resident burning brush on his property last Sunday afternoon.Residents aren’t the only ones burning.That smoke you see on the horizon is from dozens of brush fires set by the developer as he continues to clear land.Here’s one still smoldering.At this point, a major storm would bring the potential for uncontrolled erosion,just as it did in Woodridge Village in Montgomery County, above Elm Grove.As dry as it has been lately, the developer is burning brush piles next to woodlands. That increases fire risk. The barren surface also accelerates runoff and erosion, increasing flood risk.Note the haze and plums of smoke on the horizonand the vast expanse of exposed, packed dirt.The smoke is coming from burning piles of brush, such as these. If a fire spread into surrounding woods, local volunteer fire departments would be overwhelmed.No fire hydrants anywhere in sight.
If this were Houston, hydrants would be spaced at a minimum of every 500 feet. A firefighter told me that the spacing often depends of home values and population. Based on population alone, he believes this area should have hydrants.
One Small Detention Pond for 15,000 Acres
The developer has one detention pond (center) for the entire 15,000 acres. He relies on less efficient, in-ditch detention for additional capacity.Note the proximity to SH99 in the upper right.There are no detention ponds anywhere in the new areas being cleared. This is reminiscent of Woodridge Village which contributed to the flooding of hundreds of homes in Elm Grove.But Woodridge was only 268 acres. The developer relies on this and other drainage ditches to double as detention ponds in storms. But at the far end of this ditch……FM 1010 washed out during Harvey and destroyed one of the two major access roads into the development. The in-ditch detention failed. So has the county. The road has been out now for 1025 days, increasing the commute time for residents and the response time for firefighters.
Endless Loop of Construction and Destruction
State Highway 99 represents more than just a third loop around the City of Houston.
SH 99 will bring more developersand more people eager to escape downstream flooding issues.
Tapayer funded roads such as these create endless loops of construction and destruction. They are like a perpetual motion machine. Building one area floods another, causing people to move farther out and the cycle to repeat itself.
No one will admit it’s intentional, of course. The flooding is just a byproduct of greed. Cut a detention pond here. Substitute in-line detention there. Don’t bother planting grass to reduce erosion. Send your problems downstream. Let someone else worry about them.
One Chance
Do all developers think that way? Of course not. Many have principles and wonderful communities to show for them.
That notwithstanding, as one Splendora resident said, “They really only have one chance to get this right. If they screw this up, it will be almost impossible to fix and they will argue over who is going to pay for it for centuries.”
We are at that inflection point now.
Posted by Bob Rehak on 6/19/2020
1025 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.
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2020/06/20200616-RJR_3705.jpg?fit=1200%2C800&ssl=18001200adminadmin2020-06-18 21:28:292020-06-18 21:57:39“The Developers Are Coming! The Developers Are Coming!”
Construction of State Highway 99, also known as the Grand Parkway, has turned south. It is now approximately 4.5 miles from FM1960, but more than 20 miles from reaching its goal of I-10. In the image below, taken on 6/16/2020, you can see it crossing the Luce Bayou Inter-Basin Transfer project and then heading through open farm land.
Looking southeast. Grand Parkway construction has now passed the Luce Bayou Inter-Basin Transfer Project. Approximately 4.5 miles remains before construction reaches FM1960 to the south.
The Grand Parkway will open up vast areas in Montgomery, Harris and Liberty counties for development. All of that will put pressure on Lake Houston, shown in the lower left of the satellite image below (which was taken seven months ago.
Now, more than ever, it’s important for these counties to work together to reduce the risk of flooding for downstream residents in Houston, which is the economic center of the region.
Without a vital, safe center, growth in the entire region could falter.
Posted by Bob Rehak on 6/18/2020
1024 Days after Hurricane Harvey
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2020/06/20200616-RJR_3555.jpg?fit=1200%2C800&ssl=18001200adminadmin2020-06-18 15:33:432020-06-18 15:33:53Grand Parkway Construction Now Within 4.5 Miles of FM1960
In April, Harris County Commissioners directed the County Engineer and Executive Director of the Flood Control District to recommend minimum drainage standards for all communities in Harris County. The idea: to protect the County’s $2.5 billion flood bond investment. Lax standards in one place could undermine mitigation projects in another.
High-Level Recommendations
In May, the two executives came back to Commissioners Court. Here is what they recommended. These ideas apply to all cities within Harris County as well as those outside the county, but which drain into Harris County.
The recommendations must be adopted within municipal boundaries AND extraterritorial jurisdictions by December 31, 2020, IF the municipalities in question wish to partner with the county on any flood bond projects. That’s a $2.5 billion stick the county wields and that’s a powerful incentive.
Here are the recommendations:
Use Atlas 14 rainfall rates for sizing storm water conveyance and detention systems.
Require a minimum detention rate of 0.55 acre feet per acre of detention for any new development on tracts one acre or larger in size. However a single family residential structure and accessory buildings proposed on an existing lot is except from providing detention.
Prohibit the use of hydrographic timing as a substitution for detention on any project, unless it directly outfalls into Galveston Bay.
Require no net fill in the current mapped 500-year flood plain, except in areas identified as coastal zones only.
Require the minimum Finished Floor Elevation (FFE) of new habitable structures be established at or waterproofed to the 500-year flood elevation as shown on the effective Flood Insurance Study.
County Has Hired Engineering Firm to Identify Specific Changes
The County has hired an engineering firm, EHRA Engineering, to assist communities in evaluating and updating their policies and ordinances at no cost to the community.
End-of-Year Deadline
To help ensure participation, no partnership projects, including flood control or county roadway projects, will be constructed after December 31, 2020, in communities that have failed to implement these minimum standards. Projects started before that date may be continued only if communities are actively working to update their criteria.
Fix Flooding First Initiative About to Be Unveiled
The letter, signed by John Blount, Harris County Engineer, and Russ Poppe, Executive Director of Harris County Flood Control, also hints at something called a “Fix Flooding First” Initiative scheduled for roll out later this month. A Google search for “Fix Flooding First” turned up an initiative in Charleston, SC, but nothing in Harris County yet. Stay tuned.
Exact Text of Language Approved by Commissioners
Below is the exact text of the language in the two page letter unanimously approved by Commissioners and the County Judge.
The reference to hydrograph timing in the letter above refers to the Beat-the-Peak exemptions that Montgomery County offers to developers as an alternative to detention ponds. If developers can prove that their runoff will reach a river or stream BEFORE the peak of a flood, they can avoid building detention. The theory is that they aren’t adding to the peak.
The Artavia Development near FM1314 and the West Fork covers 2200 acres without having one detention pond. Ditches are designed to get water to the river ASAP.
Of course, that only encourages developers to get water to a river faster in a flood. That reduces the time of accumulation and adds to flooding downstream. It’s the exact opposite of what should happen to reduce flooding.
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2020/06/20200421-RJR_0841.jpg?fit=1200%2C800&ssl=18001200adminadmin2020-06-07 18:31:372024-02-07 12:32:46Minimum Drainage Standard Recommendations for Communities In or Draining Into Harris County
In March, Montgomery County Commissioners voted to sue a new sand mine operating near the Carriage Hills subdivision of Conroe. The county attorney sought to force the mine to remove unspecified materials from the West Fork floodway while they resolved permit issues. Since then, according to residents, the mine has voluntarily suspended operations.
Aerial Photos/Maps Show Mine in Floodway
However, a flyover on 4/21/2020 revealed that mining, processing, and transportation equipment remains in the floodway.
New mine in San Jacinto West Fork floodway near Carriage Hills (background on left) in Conroe.Reverse angle. Floodway cuts between homes in foreground and mine in background. River concealed by trees in background.See FEMA flood map below.Cross-hatched area = floodway. Aqua color represents 100-year floodplain. Brown = 500-year floodplain. Source: FEMA.
From 600 Truckloads a Day to Nothing
The once bustling operation with 600 trucks per day coming and going down Carriage Hills Boulevard now seems eerily quiet. It’s not clear whether the suspension of operations relates to the County lawsuit, COVID, a drop in demand due to the economic downturn, or all of the above.
Close up shot of operations.Residents say that before suspension of operations, the mine was running up to 600 trucks per day up Carriage Hills Blvd. leading to top of photo.A second, smaller part of the operation.Another sand mining operation brackets the other side of Carriage Hills.
Residents Fear Resumption of Activity
While residents enjoy the quiet, they see it as temporary. They fear that once the COVID crisis passes and the mine resolves its permit issues, the round-the-clock truck traffic will quickly return.
Indeed, the Montgomery County Engineer’s Office, indicates that the owner of the new mine has re-applied for a permit. That permit is now under review.
Even if you see zoning as a communist conspiracy, as some in Montgomery County do, being surrounded by sand mines kind of makes you a believer in large-scale, master-planned communities.
So much for those idyllic little hideaways in the woods.
Posted by Bob Rehak on 4/27/2020
972 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.
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2020/04/20200421-RJR_0611.jpg?fit=1200%2C800&ssl=18001200adminadmin2020-04-27 14:19:092020-04-28 10:54:01Carriage Hills Sand Mine Still Has Equipment in West Fork Floodway
Montgomery County commissioners will vote Tuesday whether to sue a new sand mine on the west side of the San Jacinto West Fork. The mine is in a Conroe development called Carriage Hills.
Page 1 of the document above says that, “… it appears that MBM Sand Company, LLC and Carl Hudspeth, individually and doing business as Skilled International, LLC have violated, is violating, or is threatening to violate Subchapter I of Chapter 16 of the Tex. Water Code, or one or more rules adopted by Montgomery County under said subchapter and has failed and refused to cease and desist as demanded by the Montgomery County Engineer and/or the Montgomery County Attorney.”
The county seeks both injunctive relief to remove illegal improvements and restore preexisting conditions. The county also seeks monetary fines totaling $100 for each act of violation and each day of violation.
The complaint, however, does not enumerate specific alleged violations.
Depending on alleged violations, the outcome of this could set a precedent for other sand mines operating on the West Fork.
Homeowners Have Additional Complaints
The mine also faces problems from local homeowners.
The mine is operating adjacent to a once-quiet neighborhood called Carriage Hills in Conroe. It is sending heavy trucks weighed down with sand up and down Carriage Hills Boulevard. Residents say the noise exceeds 85 decibels, the trucks have torn up roads, and they fear for their children’s safety.
The trucks, as many as 12 at a time, begin idling outside the plant gate at 6:30 a.m. and run up and down Carriage Hills Boulevard hundreds of times a day – by one count 600 times.
They believe 600 dump trucks a day at intervals of 2 minutes or less, starting at 6:30 a.m. “substantially interferes” with their ability to enjoy their land and that it causes “unreasonable discomfort or annoyance.”
The operation will not end anytime soon without a restraining order. The company is just now removing the overburden, trying to get to frack sand.
Only Restraining Order Will Stop Operation Now
Homeowners believe the operation will likely devalue their properties.
They also worry about the safety risk to children given the high volume of industrial vehicles with tons of payload traveling at speeds that make them unable to stop to stop quickly on residential streets.
Some of the residents plan to present the petition to commissioners tomorrow.
Posted by Bob Rehak on 3/23/2020
938 Days after 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.
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2020/03/Two-Trucks.jpg?fit=1200%2C677&ssl=16771200adminadmin2020-03-23 21:10:532020-05-25 05:34:12MoCo Will Vote Tomorrow on Whether to Sue New Sand Mine in Carriage Hills
LJA Engineers submitted a master drainage plan for the 2,200 acre Artavia development that Montgomery County approved. It has no detention ponds. And the drainage channels currently do not connect to the San Jacinto river. Even though LJA said they would connect to the river, the plans do not specify how, when or where. As you will see below.
Dead-end drainage. Currently, the Artavia drainage channel stops just short of the Liberty Materials Moorehead mine in the background. The San Jacinto River lies beyond the mine. This and all other aerial photos below were all taken March 6, 2020.
A Sand Mine Is Not the San Jacinto
The plans DO show the channel terminating in a sand mine between Artavia and the river. A spokesman for the sand mine said the developer is still trying to work out environmental and easement issues.
Aerial photos show the main channel stops about a 100+ yards short of LMI’s shipment facility. Meanwhile, during heavy rains, the dead-end drainage overflows onto surrounding properties. A spokesman for the mine claimed that the overflow flooded the mine last year and caused the dikes to break. He alleged that was the proximate cause for 56 million gallons of white sediment-laden water entering the West Fork.
Exhibit 2 of Artavia Drainage Impact Analysis from 9/20/2018 shows the project outfall in the middle of the LMI sandpit that borders Moorehead Road and the San Jacinto West Fork in Montgomery County.
The project manager for LJA did not return calls to explain their position on the dead-end drainage. And when asked for an explanation, the new Montgomery County Engineer (not the one who signed these plans) only referred me back to LJA.
Below are the drainage plans for Artavia, obtained by a Freedom of Information Act request to Montgomery County.
Several things have jumped out at me so far. LJA has not yet returned phone calls, so to me they remain…
Unaddressed Issues
Elevation Change Accelerates Flow
Elevation drops suddenly as you get near the river – 12 feet. That accelerates waterflow and threatens the sand mine. As you can see above and below, the channel is like a firehose aimed at the mine. That mine has enough problems of its own. In the past, dike breaches have affected Lake Houston water quality; we don’t need more of that. The mine blames the breaches on water overflowing from the Artavia ditch.
Note how the water in this short section of Artavia’s drainage ditch does not even pond at one end and reaches halfway up the banks at the other. That shows the slope. The SJR West Fork is between the two sections of the mine in background.
Flow Rates Understated
LJA calculations appear to understate the volume and velocity of flow. They use a Manning’s coefficient of .035, a value associated with pasture/farmland or channels filled with stones and cobbles. The coefficient recommended for smooth channels is 0.022. The difference creates a 63% increase in velocity and a 60% increase in volume of flow.See for yourself. With no real way yet for the water to get to the river or under FM1314, that will cause water to pile up much faster.
Not too many cobbles and boulders in this channel.All sand and siltwhich is already blocking culverts.
LJA also uses pre-Atlas rainfall statistics in their calculations of 10-, 25- and 100-year peak flows. The new Montgomery County standard is 16.1 inches in 24 hours compared to the 12.17 that LJA used for the 24 hour, 100-year flood.
Did LJA use “good engineering practices” and model Atlas 14 to ensure that it actually contained the 100-yr, 24-hr storm? There’s an ethical issue here. Did they put public safety first? We don’t know because they didn’t say so in any of their documents.
No Mention of Wetlands
LJA never mentions wetlands in their analysis. However, the National Wetlands Inventory shows wetlands on Artavia property and other property Artavia drains through.
Wetlands on Artavia Property or property Artavia drainage would likely have to go through.
Threat to Pipeline
A pipeline crosses the Liberty Materials mine. High velocity flow through the mine could undermine and threaten that pipeline like it did at another Liberty mine and at the Triple PG mine on the East Fork.
Green line shows path of pipeline across across Liberty Materials Mine. White line shows current path of drainage ditch.
No Outlet
There’s no explanation for how Artavia will get water through the pit at the end of their ditch. They can not store Artavia’s runoff in the pit. Their pit is already filled to the brim with highly silty, turbid water. Another unauthorized discharge could affect water quality in Lake Houston...again!
Level of water in the pit that Artavia’s ditch would have to drain through. Pit is already overflowing. West Fork is in background.TCEQ measured suspended solids in pit’s water at 25X higher than river.
Threat to Mine
A representative for the mine owner says the mine owner doesn’t want more water in the pit. They can’t afford the cost from environmental or business perspectives. With the COVID-19 threat, construction activity is way down. So margins are slim. And they can’t afford to have water fill their deep pit where they dry mine.
“No Adverse Impact”
LJA claims the project will have no adverse impact on downstream properties. But it already has. Properties along Greenbaugh and in Oak Tree have flooded since Artavia started clearing land and filling in wetlands.
Oak Tree detention pond (behind camera) used to overflow into wetlands. Then Artavia started clearing and filling. Now water backs up into the 40+ homes in the small subdivision.
The Liberty Materials mine also alleges it was flooded by Artavia’s overflow, resulting in the discharge of 56 million gallons of silty water into the West Fork.
LJA can only convey 68 cfs under FM1314. Meanwhile, TxDoT has not yet finished the design for a bridge. They hope to start bidding the job by the Fall of this year. Residents, not the developer, will pay for the improvement through the local municipal utility district.
Artavia ditch on north side of FM1314Where water exits on the downstream side of FM1314Channel downstream/south of FM1314.
LJA claims “The culvert crossings were designed to have capacity to convey 100-year storm events.” But they certainly aren’t doing that now.
Diverting Water From East to West Fork
The developer appears to be diverting water from the East Fork watershed to the West Fork watershed. See Section 1.4 and Exhibit One.
It would be harder to “beat the peak” to the East Fork. It’s 12 times farther away; water would take much longer to get there. So the diversion appears to be an attempt to avoid building detention ponds. But the diversion adds to flood volume in heavily populated West Fork areas where far more homes flooded during Hurricane Harvey.
Will LJA Figure It Out In Time?
For the sake of adjacent residents and businesses, let’s hope they figure these loose ends out before the next flood.
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.
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2020/03/20200306-RJR_9170.jpg?fit=1200%2C800&ssl=18001200adminadmin2020-03-20 20:48:012020-03-20 23:58:19The MoCo/LJA Way: Build First; Work Out Drainage Details Later
It all seemed somewhat academic at the time – unless you previously flooded from upstream development. Then along came Imelda. The absence of functioning detention ponds on Perry Homes’ Woodridge Village property underscored the need for adequate detention for the second time in five months when hundreds of homes downstream in Kingwood flooded.
The engineering company for the developer, Aliana, claims their calculations show that floodwater from Artavia will beat the peak of a flood to the West Fork by 35 hours. Dasa Crowell, PE, LJA’s Project Manager for Hydrology and Hydraulics, thus concluded, “This leads us to a conclusion that the peak flows generated by the runoff from project drainage area will have no impact on the WFSJR under proposed conditions, therefore detention is not required.” See page 56 of this PDF.
In fairness, the development does include a retention pond in Section 1 labeled as a detention/amenity pond. However, aerial photos show that it has only a few feet of excess storage capacity above its normal water surface elevation. See the plans here. It’s certainly not going to hold back a 100-year rain falling over 2200 acres.
Little Buck Amenity Facility/Pond. Note that as-built conditions appear smaller than plans.
Engineers seem to be relying on drainage channels to act as their detention basins, but as we will see, that comes with some risk. And one potentially bad assumption may invalidate the whole concept.
Because detention costs money and limits the number of salable lots, developers try to get their water to the river as quickly as possible so they can “beat the peak.” Of course, racing to get water to the river in a flood is the exact opposite of what you want to happen if you are a downstream resident. Normally, you want developers to hold water back as long as practical so as not to overwhelm downstream channel capacity.
Wilds said in part, “The analysis … demonstrates that the peak flow from the developed tract will pass through the downstream cross-section approximately 35 hours prior to the peak flow from the upstream watershed. The report indicates that the 10-year, 25-year and 100-year events were analyzed and concludes that the runoff from the project drainage area will have no impact to the San Jacinto River under proposed conditions.”
“Based on this information, this office offers no objection to the analysis as presented. Storm water detention will not be required for this development as long as the developed flows up to and including the 100-year event can be adequately conveyed to the San Jacinto River.” For the full text, see page 51 of this PDF.
The Executive Summary of the most recent update of the drainage impact analysis for Artavia states, “The November 2014 memorandum documents the analysis supporting no detention requirement; this analysis provides calculations showing that the proposed Star Ridge Ranch development (as it was then called) drainage system will safely convey the rainfall runoff for rainfall events up to and including the one-percent annual chance (100-year) storm event.”
Similarities Between Woodridge Village and Artavia
Finally, LJA pushed both the Woodridge and Artavia plans through the MoCo Engineers office right before the drainage criteria manual was about to be updated again with more stringent requirements.
LJA submitted both drainage analyses for MoCo approval within approximately a year of Hurricane Harvey before flood maps, rainfall statistics, drainage criteria, and construction standards were updated.
LJA Engineering was not only playing beat the peak, it was playing beat the clock again. This will be the first of several posts on Artavia. More news to follow.
Posted by Bob Rehak on 3/17/2020
931 Days after 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.
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2020/03/20200306-RJR_8998.jpg?fit=1200%2C800&ssl=18001200adminadmin2020-03-17 21:29:282020-03-17 22:31:30LJA Engineers 2200-Acre Artavia Development in Montgomery County Without Detention Ponds
