At the current rate that crews are removing sand from the West Fork San Jacinto Mouth Bar, the remainder of the above-water portion of this once-behemoth sand bar could be gone by Christmas. See the two pictures below. The first taken after Harvey and the second taken today.
These two shots show the West Fork mouth bar two weeks after Harvey and today…more than three years later.
Much Yet to Dredge
Of course, even when the above water portion of the Mouth Bar is removed, that will still leave a huge portion below the surface. However, all progress is welcome.
Like an iceberg, most of a sand bar exists below the waterline.Photo taken 10/26/2020.I can’t say with certainty that this is submerged sand, or water stirred up by dredging. It seems too uniform to be the latter. Compare the picture below looking toward the WLHP bridge from a slightly different position and note how irregular the stirred-up sediment looks.Also note that the picture above was taken upstream from the current dredging.
At the start of October, the above-water (sub-aerial) extent of the mouth bar was down to the width of one excavator. Two excavators are now working toward the middle from each end. See below.
Looking WNW toward the West Lake Houston Parkway Bridge and Kings Harbor.Taken 10/26/2020.
From the wet mark on this excavator’s arm, it looks as though they are excavating up to 10 feet below the waterline. The 10-foot estimate closely agrees with the profile chart below.Taken 10/26/2020.
Like an Iceberg, Most of a Sand Bar Exists Below Water
That’s significant progress given what we started with. But much sand remains below the surface.
Tim Garfield and RD Kissling, two leading geologists now retired from one of the world’s largest oil companies, mapped the depth of the river using sonar and depth poles. They found an underwater plateau exists in this region of the river. See chart below.
The blue line represents the water surface. The gold line indicates the deepest part of the channel as you move downstream from the WLHP bridge to the FM1960 bridge. Numbers on the left scale indicate water depth. Numbers on the bottom scale indicate distance in feet downstream from the WLHP bridge.
Plans for Next Phase Still Not Revealed
FEMA has approved dredging another million cubic yards. And Dan Huberty’s amendment to SB500 in the last legislature dedicated $30 million for dredging the West Fork Mouth Bar. The City is drawing up plans, but they have not been announced yet. The last time I talked to Stephen Costello about this, he said the City was leaning toward dredging a channel somewhere south of the mouth bar. But many details remained to be worked out, such as:
Method of dredging (hydraulic vs. mechanical)
Exact location
Channel width
Finding qualified contractors
Bidding
Determining a suitable placement area, etc.
More news when its available.
Posted by Bob Rehak on 10/26/2020
1154 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/2020/10/BeforeNow.jpg?fit=1200%2C1200&ssl=112001200adminadmin2020-10-26 17:09:182020-10-26 17:09:22Above-Water Portion of Mouth Bar Could Be Gone by Christmas
Since June, I’ve posted about problems in the Colony Ridge development in Liberty County. Among them: the washout of FM1010 where it crosses over Rocky Branch. Authorities have closed the busy road which provides access to Colony Ridge for three years, forcing tens of thousands of residents to seek alternate access routes, such as FM1485 and FM2090.
However, it’s difficult to see all the damage. So today I took a drone and captured some previously unseen details.
Colony Ridge drainage ditch leading to Rocky Branch contributed to washing out FM1010 at far end of ditch.
Lack of Functional Detention Capacity Likely Contributed to Washout
The damage is likely the result of inadequate, poorly engineered, or poorly maintained detention. Another contributing factor: a steep drop in elevation as water leaves the massive ditch (see above) in Colony Ridge and descends through a wooded area toward FM1010. That drop accelerated more water than should have been traveling down Rocky Branch, an East Fork San Jacinto tributary. As a result, floodwaters swept trees and other debris downstream.
One Thing Leads to Another
The debris:
Clogged culverts under the road…
Then, when the roadbed became a dam…
…Water churned through the roadbed next to the culverts…
…And deposited more “beaver dams” downstream…
…that, in turn, contributed to the flooding of surrounding homes.
Years of Neglect Still Ignored
Amazingly, no one in Liberty County corrected these problems after Harvey. As a result, many homes flooded again in 2019, during heavy downpours on May 7th and September 19th. The problems still have not been fixed. See the pictures below. I took them this afternoon.
Just yesterday, I had lunch with a couple who were considering moving to Liberty County because they were seeking a quieter lifestyle. I told them about this story. They are reconsidering.
FM1010 Washout at Rocky Branch has not been repaired for more than three years. Note flood debris clogged in culvert. Also note straps around logs!
“Beaver dam” just downstream from culverts is building up and up, contributing to additional flooding.
Not All Business is Good Business
Colony Ridge has grown into the world’s largest trailer park in less than a decade. It brought more than its fair share of problems:
Legendary traffic backups – even on Sunday afternoons.
A hard lesson for some people to learn is that not all business is good business. Lax enforcement of regulations allowed Colony Ridge to grow out of control. Now county commissioners have a nightmare on their hands, cannot fix their problems, and cannot enforce their own regulations.
Posted by Bob Rehak on 10/25/2020
1153 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/2020/10/20201025-DJI_0919.jpg?fit=1200%2C900&ssl=19001200adminadmin2020-10-25 21:08:132020-10-25 23:49:28New Drone Shots Reveal Need for Better Flood Control in Liberty County
Hurricane Watches issued for eastern and northern coasts of the Yucatan peninsula.
(Sunday 8am, October 25, 2020) The tropical depression over the northwestern Caribbean Sea has continued to slowly become better organized. Satellite and hurricane hunter aircraft have determined that winds increased to near 40kts. Overall Zeta has not moved much in the last 12 hours. However, Zeta should approach the Gulf Coast Tuesday night or Wednesday. It will bring storm surge, rainfall and wind impacts from Louisiana to the Florida panhandle. The storm poses no immediate threat to the Houston Area.
Track
Zeta will have little forward motion for the next 12 hours; steering flow is weak. However, on Monday mid-level high pressure will begin to build westward letting Zeta turn NW and WNW, and to increase forward motion. Global model guidance is in good agreement on this track. Zeta will then enter the southern Gulf of Mexico. A strong cold front will push south and east across the Great Plains by mid-week. and turn Zeta north and likely northeast toward the central or eastern US Gulf coast. However, much uncertainty exists on how sharply Zeta will turn. The storm could make landfall anywhere from Louisiana to the Florida panhandle.
Intensity
Overall Zeta is in a favorable environment for development. Zeta could approach hurricane intensity as it nears the Yucatan. Once in the Gulf of Mexico conditions continue to look favorable for intensification. Zeta will likely regain or maintain hurricane intensity.
However, as Zeta begins to turn northward toward the central Gulf, cooler sea surface temperatures and increasing vertical wind shear should weaken the system. No one knows at present how quickly weakening may occur.
A slight chance exists that tropical storm force winds could extend into areas east of Houston and Galveston Bay.
NOAA/NESDIS/STAR GOES ABI BAND 13 shows Zeta’s intensity building in the NW Caribbean.
Posted by Bob Rehak on 10/25/2020 based on information from Jeff Lindner, HCFCD, and the National Hurricane Center
1153 Days after Hurricane Harvey
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2020/10/image002.png?fit=897%2C736&ssl=1736897adminadmin2020-10-25 09:51:202020-10-25 10:01:47It’s Official; Zeta, Yet Another Tropical Storm Forms
The tropical wave in the NW Caribbean that I posted about this morning has become better organized. It now has a broad low-level center southwest of the Cayman Islands. Low- and mid-level centers are currently not aligned, but conditions favor eventual alignment. There are numerous curved bands and weak to moderate scattered convection near the low level center.
Like so many other storms this season, this one should veer east before it hits Houston. TD 28 will move into the southern Gulf of Mexico by early next week. But an approaching cold front over TX will turn it toward the east. Major global models agree on the track with the exception of the European model which brings it in over Louisiana. This model has had a significant west bias this hurricane season with Laura, Sally, and Delta. Other models take it toward the central or eastern US Gulf coast from SC LA to the FL panhandle.
Intensity
Conditions are favorable for development with plenty of moisture and warm sea-surface conditions. NHC forecasts a hurricane in the southern Gulf of Mexico by Tuesday. After Tuesday, it may weaken as the system lifts northward over the Gulf of Mexico. Similar to Delta, with an incoming trough from the west, an expansion of the wind field will be possible over the northern Gulf of Mexico.
Afternoon satellite image on 10/24/2020NOAA/NESDIS/STAR GOES ABI BAND 13 shows intensity.
Threats
The system should approach the northern Gulf Coast as a tropical storm on Wednesday, and could bring storm surge, rainfall, and wind impacts to areas from Louisiana to the Florida Panhandle. Residents in these areas should monitor the progress of the depression and updates to the forecast.
Posted by Bob Rehak at 5 pm on 10/24/2020 based on info from HCFCD and the NHC
1152 Days since Hurricane Harvey
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2020/10/image001-4.png?fit=897%2C736&ssl=1736897adminadmin2020-10-24 17:16:162020-10-24 17:16:21Tropical Depression Forms over NW Caribbean; Threatens U.S. Gulf
The Great Lakes dredge that liberated River Grove Park from a sandbar more than 10 feet high and a quarter mile long.
The company has many other interests in the Houston Area and the central Gulf Coast from Corpus Christi to Louisiana. The move puts the company closer to key customers and growing markets, especially along the Gulf Coast and Mississippi River. The company already has regional offices in Jacksonville, FL and Staten Island, New York.
The company deepens ports, maintains waterways, renourishes beaches and restores barrier islands.
About the Houston HQ
The Houston headquarters, scheduled to open in early 2021 with its executive leadership team, will be staffed gradually over the next 12 months. It is initially searching for 20,000 square feet of office space in the Energy Corridor, between the Galleria and Beltway 8. The company will maintain a business and operations support center in the Oak Brook area.
The company said the move also will allow it to leverage long-term relationships with the Center for Dredging Studies at Texas A&M University, Louisiana State University and other universities that feature coastal resilience and natural infrastructure initiatives.
Landmark Projects Throughout US
Great Lakes has been involved in the development and construction of many well-known landmarks. In the Great Lakes’ region, that has included Chicago’s Navy Pier and Michigan Avenue Bridge; straightening and reversing the flow of the Chicago River; Northerly Island, a 91-acre peninsula along Chicago’s Lake Michigan; and the deepening the St. Lawrence Seaway between the U.S. and Canada.
Elsewhere, it has completed deepening projects in almost every port in the country and worked on important infrastructure projects, such as the massive container terminals in the ports of Los Angles and Long Beach and the Fort McHenry Tunnel that carries interstate traffic underneath the Baltimore Harbor.
Recent Texas and Louisiana Projects
Among its recent projects in Texas and neighboring states: deepening the Corpus Christi Ship Channel from the Gulf of Mexico to Harbor Island; maintenance dredging of Houston Ship Channel; dredging for liquefied natural gas facilities in Corpus Christi and Cameron Parish, La.; restoring Louisiana’s Whiskey Island, which helps protect Terrebonne and Lafourche parishes from storm surge; restoring barrier islands to protect coastal Mississippi; and building the barrier berms that protected Louisiana from the Deepwater Horizon oil spill.
Works in Almost Every Port in County
Elsewhere, it has completed deepening projects in almost every port in the country and worked on important infrastructure projects, such as the massive container terminals in the ports of Los Angles and Long Beach and the Fort McHenry Tunnel that carries interstate traffic underneath the Baltimore Harbor.
The company is the largest provider of dredging services in the US. It has a fleet of more than 200 vessels.
Welcome to Houston!
It will be good to have such a valuable resource in Houston. Especially as sediment builds up in our rivers and lakes to the point where it can no longer be ignored. Great Lakes’ expanded presence will make the Houston dredging market even more competitive.
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2018/10/SJR_288_016.jpg?fit=1800%2C824&ssl=18241800adminadmin2020-10-24 16:28:592020-10-24 16:30:13Great Lakes Dredge and Dock Moving Corporate HQ to Houston From Chicago
A tropical depression or tropical storm is likely to form over the NW Caribbean Sea. However, at THIS TIME, it poses no threat to southeast Texas.
Could Become Tropical Storm Zeta
Jeff Lindner, Harris County Meteorologist says, “A slow moving tropical wave over the NW Caribbean Sea is becoming better organized. A tropical system will likely form in the next 24 hours. The system will move generally slowly toward the NW over the next 48 hours and into the southeastern Gulf of Mexico.”
Conditions currently favor some development, but upper level winds over the Gulf of Mexico may become hostile for additional development by early to mid next week. The overall track is in the general direction of the central or eastern Gulf of Mexico over the next 4-5 days.
Too Early To Predict Landfall
It’s too early to tell where this will make landfall. But NOAA’s satellite images show it definitely becoming better organized.
This shows circulation starting to form. Note the bands of clouds starting to dance around each other.
The National Hurricane Center gives this system a 90 percent chance of becoming a tropical depression or storm in a day or two. If it becomes a storm, it would be Zeta.
Most models currently take the storm east of us.
What Climatology Says
This is a reminder that we still have five weeks left in the 2020 hurricane season.
At this time of year, storms are most likely to track toward Florida, but as you can see above, the western Gulf is also a likely target.
Posted by Bob Rehak on October 24, 2020 with thanks to Jeff Lindner and the NHC
1152 Days since Hurricane Harvey
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2020/10/two_atl_5d0-3.png?fit=900%2C665&ssl=1665900adminadmin2020-10-24 10:29:192020-10-24 10:29:23New Tropical System Has 90% Chance of Developing in Gulf
After Harvey, the US Department of Housing and Urban Development (HUD) made $1.3 billion in disaster recovery funds available for housing assistance to the City of Houston through the Texas General Land Office (GLO). The City kicked off several disaster recovery programs with great fanfare in January of 2019. However, in almost two years, the City has only helped 1.4% of eligible applicants for assistance and an estimated 0.5% of those who flooded without insurance. The second figure includes flooded homeowners who could have applied, but didn’t.
City of Houston Housing and Community Development on January 14, 2019. Mayor Turner said, “Thousands of Houstonians who were affected by Hurricane Harvey have been waiting for this day.” Most are still waiting.
Programs Announced in January 2019 Quickly Fall Behind Schedule
The programs were primarily designed to repair and reconstruct single- and multi-family homes, and to reimburse owners for repairs they made. However, almost from the outset, the program failed to reach its own goals and has fallen progressively farther behind.
A HUD audit in November of 2019 panned the City for failure to staff the program adequately. It also expressed concerns about the City’s lack of transparency, not posting plan documents online, not bidding contracts competitively, failure to follow HUD rules, and failure to meet objectives.
GLO Attempts to Help Rebuffed by City
The GLO, which is responsible for overseeing the program and ultimately for the money itself, sent a “strike force” to assist the City, train employees and get the programs back on track. However, the Director of the City’s Housing and Community Development Department, which conducts these programs, told the GLO’s strike team they were not welcome and told them to leave the Department’s office, according to Brittany Eck, a GLO spokesperson.
As the City fell further behind schedule in 2020, the GLO tried to take over some of the programs. Eck says GLO wanted to help the City focus on those where it had more success. However, the City also rebuffed those efforts. The City filed a lawsuit to prevent the GLO from taking back the programs. Ultimately, HUD stepped in and approved an “Action Plan Amendment” that resulted in cancelation of the City’s contract.
Other programs for reconstruction, repair and rehab expire in 2024. But it takes time to design, permit, bid and construct homes. And it takes even more time to get approvals through the City, GLO and HUD. So…
According to the GLO, even the 2024 deadline is in jeopardy at this time.
Reimbursement Program May Come Back to City
The GLO reportedly may give the reimbursement program back to the City. With only two months left before the deadline, GLO doesn’t have time to get program changes approved through HUD, transfer files, and still reimburse flood victims who paid out of pocket for reconstruction.
But it’s unclear whether the City will commit to meeting all of the GLO’s performance benchmarks and deadlines. No one at the City will comment publicly. Eck said no commitments had yet been made, but might come as early as the end of today.
Reasons for Clawback of Some Programs
We’ve all heard the news reports about the City’s performance or lack thereof. But aside from the small number of homes completed, reports don’t go into much detail. Eck, the GLO’s spokesperson, spent hours explaining the complexities behind published numbers.
First, let me say, it’s difficult to compare the State’s numbers with the City’s. The two entities refer to programs differently. And they sometimes reflect different time periods or different stages of completion.
Plus, the City generally reports numbers for itself that are higher than the GLO’s numbers for the City. However, the differences are so small in the grand scheme of things that they get lost in rounding. So to eliminate charges of political bias, I have simply accepted the City’s numbers in almost all cases for the analysis below, except where the City does not supply numbers.
High-Level Findings
The deeper you dig, the more several things become clear:
1151 days after Hurricane Harvey, less than 1.5% of eligible recipients in Houston have received help so far. And that may be a generous overstatement.
Houston has repeatedly failed to meet its own projections.
Let’s address the first point and cover the others in later posts.
Application Process Started with Pre-qualification Survey
First, you need to understand the two-step application process. First, the City conducted a survey to screen applicants. Second, those who appeared to qualify were invited to apply for aid.
21,156 households took the survey. Of those, the City estimated 16,651 qualified for some kind of aid. See the screen capture below taken from the City’s website.
Many Still Waiting for Invite to Submit Application
Many families who qualified are still waiting to be invited to submit an application. The last “situation and pipeline” report posted on the City’s website shows 6,541 households “Pending invitation” as of 8/31/2020 (see page 6).
On the right side of the diagram above, the City also says that it sent out “Notices to Proceed with Construction” for another 149 homeowners. Those notices covered almost another $32 million. Those average $214,765 per household. But construction has not yet finished on all of those.
So that’s roughly 100,000 homes without flood insurance (a major qualification for HUD grants).
The City has half the population of the county. So, let’s assume that approximately 50,000 householdsflooded in the City that could have theoretically applied for assistance. But according to the City graphic above, only 21,000 households took the survey. And the City says 16,651 of those were eligible (about a third of flooded homes without insurance).
But regardless, if you accept the City numbers, they have helped 231 families so far (82 + 149) out of 16,651 eligible survey respondents. And that doesn’t even include another 30,000 families that didn’t take the survey!
So, in almost two years, the City has only helped 1.4% of eligible survey respondents. And roughly 0.5% of those who flooded without insurance.
Calculated from data supplied by City of Houston and Harris County Flood Control District
$800 Million in Disaster Relief Remains Uncommitted At This Point
When you add in the number of projects in the pipeline (identified and under contract), the percentages look somewhat better. However, that cannot obscure the fact that the reimbursement program will expire in two months, and almost $800 million remains uncommitted (see circle diagram below). Now the City did not allocate all of that for reimbursing people who fixed their own homes. But they did allocate more than $400 million for homeowner assistance (see table on right below).
By the City’s own projections at the time, it should have expended $261 million by now ($1.275 billion minus $1.014 billion). However, the GLO says the City has only drawn down $24.6 million, according to Eck. That’s less than 10% of the projection the City made 16 months ago.
STATE ACTION PLAN, PAGE 254
The GLO says that the City has pushed deadlines back month after month, always using the excuse that they’re right on the cusp of turning over a large number of applications for approval.
Future Aid At Stake
Sources familiar with how HUD works indicate that non-performance on this contract could jeopardize future HUD aid to the City.
Meanwhile, I know one applicant for reimbursement who completed the City’s survey the very first day it was available. Her application still has not been processed. But, she says, the City hopes to work on it soon! That’s better than the 6,541 people still waiting for the City to invite them to submit an application.
Posted by Bob Rehak on 10/23/2020
1151 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/2020/10/Screen-Shot-2020-10-21-at-4.25.48-PM.png?fit=1654%2C904&ssl=19041654adminadmin2020-10-23 11:57:302020-10-23 12:11:51Disaster Recovery Disaster: Part 1
In three years of writing about flooding, this is one of the most dramatic case studies I have seen about the value of wetlands. It starts with a developer clearing wetlands and ends with the developer at war with a neighboring town.
Wetlands as Protectors
Michael Shrader lived in a modest home in Plum Grove in Liberty County. It was an idyllic, rural lifestyle in many ways. He did tech work remotely while raising animals on his small plot of land near the East Fork of the San Jacinto and Maple Branch. Shrader never flooded for the first 29 years he lived in Plum Grove despite living on a creek. Not in 1994. Not in Allison. Not in Rita. And not in Ike.
Forests filled with wetlands surrounded him. Water ponded during heavy rains. Much of it soaked in and was absorbed by tree roots. The creeks ran clear.
Before Colony Ridge
In this 2008 Google Earth image, you can see the vibrant greens. And if you look closely enough on a desktop display, you can even see the ponds and wetlands east of FM1010.
Note area east (right) of FM1010.
For those reading on smaller displays, here’s the same image, but with data from the US Fish and Wildlife Service National Wetlands Inventory superimposed.
The bright, solid greens represent wetlands in the national inventory. Superimposition courtesy of Michael Shrader.
Then Came the Bulldozers
In 2016, the developer of Colony Ridge started clearing land and replacing wetlands with ditches that fed into Maple Branch. It runs right behind Shrader’s home. As the developer filled in more and more of the wetlands, water started getting higher in the creek after every rain, according to Shrader. Harvey, May 7th, Imelda: those were the high-water marks. And the low points in Shrader’s life. He flooded all three times.
By last year, the developer had replaced virtually all the wetlands by this.
By 2/23/19, most of the wetlands had been turned into streets with ditches in the world’s largest trailer park. Shrader lives on a stream that cuts across the NW portion of the grid.
Since the satellite image above was taken, even more forests and wetlands farther east and north have been replaced by what is now the world’s largest trailer park.
Eastern area in June, 2020.
Slash and burn development practices at Colony Ridge. Photo June 2020.Note how contractors are draining wetland area on left.
Lives Disrupted
With the wetlands gone, Shrader’s house flooded in 2017 during Harvey (admittedly an extreme event), and twice in 2019. Not only did his house flood, so did most of Plum Grove, including the City Hall. Now, Shrader says, many homes are vacant.
The fence below, immediately downstream from the Camino Real Subdivision in Colony Ridge, was pushed over three times by the increased flow of floodwaters coming down Maple Branch. The owners of the red-roofed house bought this property just before the first of three floods.
Flooded Plum Grove home near Maple Branch and Colony Ridge. Owners stopped repairing the fence after the second flood.
At least one investigative journalist is exploring alleged predatory lending practices.
Allegations of corruption in Liberty County politics abound.
Commissioner’s Court and City Council meetings have degenerated into heated shouting matches.
Soon, Hollywood screenwriters will develop screenplays based on the Plum Grove experience and pitch them as “the next Erin Brokovich.”
Eroded drainage ditch in Colony Ridge that blew out FM1010 at far end. Three years after Harvey, the road still had not been repaired, much to the dismay of residents.
FM1010, one of the main roads into and out of the development, destroyed by out-of-control stormwater.The loss of this road has led to massive traffic jams on alternate access routes, such as FM2090.
Sadly, a little more respect for Mother Nature could have easily prevented all that trouble for the developer. One wonders whether the engineers and environmental consultants whom he hired to obtain permits served him well.
Posted by Bob Rehak on 10/22/2020
1050 Days after Hurricane Harvey and 398 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.
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2020/10/20200616-RJR_3713.jpg?fit=1200%2C800&ssl=18001200adminadmin2020-10-22 01:54:072020-10-22 09:38:22How Loss of Wetlands Led to War
The Diversion Ditch project would help address several potential problems. Expanding it would remove 62 structures from inundation areas and another 586 structures would benefit from improved local drainage. In addition, the project:
Can divert floodwater from Ben’s Branch, which will be a much more complicated project, taking more time.
Has a 300-foot right-of-way, of which only half is being used
Has bridges that already span the entire 300 feet.
Will help carry floodwaters from rapidly growing south Montgomery County.
History of Diversion Ditch
In the early days of Kingwood, Friendswood Development Company built the Diversion Ditch to reduce water flowing into Ben’s Branch. But since then, upstream development and larger rains have stressed the capacity of both Ben’s Branch AND the Diversion Ditch. Engineers estimate that peak flows have doubled since 1985.
Most of Ben’s Branch is Natural Channel
Ben’s Branch cuts diagonally through the heart of Kingwood. See red lines below. More than half its length – between Woodland Hills and Rocky Woods Drive is natural channel. Widening it will be complicated and take much time.
Red Line indicates approximate path of Ben’s Branch through Kingwood.
Ben’s Branch Now at 2-Year Level of Service
However, areas on both sides of Ben’s Branch are threatened by flooding as you can see in the image below from FEMA’s Flood Hazard Viewer.
Ben’s Branch once had a 100-year level of service, meaning it had enough carrying capacity to prevent homes from flooding in everything but a 100-year rain. Models based on new Atlas-14 rainfall probability frequencies indicate that the channel’s capacity is now down to a 2-year level of service. That means it will flood in minor rains, exactly as St. Martha School did last year.
Worse yet, Ben’s Branch has decreased to a 2-year level of service throughout its length.
HCFCD Kingwood Area Drainage Analysis
Source: Fema’s Flood Hazard Layer Viewer. Cross-hatched equals floodway, aqua = 100 year floodplain, brown = 500-year floodplain.Floodplains shown above are based on pre-Atlas-14 rainfall probability statistics. An Atlas-14 hundred-year rain is about 30-40% higher than the old hundred-year rain.
When flood maps are updated based on Atlas-14 statistics, those floodplains will likely expand…unless we do something to handle more floodwater before then.
However, Ben’s Branch will not move to preliminary engineering right away.
How to Protect Against Bigger Rains and More Upstream Development
The Kingwood Area Drainage Analysis sought to understand what we need to do to restore a 100-year level of service to all ditches and streams based on Atlas 14. Of the 19 ditches and streams studied, nine need improvement. The level of service for some, including Ben’s Branch, has been reduced to 2 years.
Expanding the Diversion Ditch is the fastest way to take pressure off of Ben’s Branch.
The Diversion Ditch intersects Ben’s Branch at the new St. Martha Church. It then flows south to Deer Ridge Park and then winds through River Grove Park. See the white line below.
Kingwood Diversion ditch (white line) intersects Ben’s Branch near the new St. Martha Church.
Expansion Capacity Already Built into Diversion Ditch
Engineers foresaw the day when Kingwood would need more drainage capacity due to upstream development in Montgomery County. They built the Kingwood Diversion Ditch to handle the extra stormwater. They also made the bridges over the diversion ditch wider than they needed at the time. Finally, they dedicated a flood easement on both sides of the ditch that was wider than they needed, so they could expand the ditch later without encroaching on neighboring properties. Here’s how it looks from the air.
Looking north across Northpark Drive toward Bens Branch, which cuts diagonally from left to right through the middle of the frame. Note the ample clearance under the bridge and the wide shoulders of the ditch. St. Martha Church is in the upper left.
Looking south toward Kingwood Drive at the Diversion Ditch. King’s Mill is on right in foreground.
Both Kings Mill and Kings Manor now drain into the Diversion Ditch. But they came long AFTER Diversion Ditch construction. Other new upstream developments that drain into the Diversion Ditch and Ben’s Branch include Brooklyn Trails and Woodridge Forest, both in Montgomery County.
As a result, the Diversion Ditch itself has decreased to a 2- to a 25-year level of service in places. However, it still offers a 100-year level of service in others.
Looking NE toward Deer Ridge Park from over Hamblen Road. A corner of Deer Ridge Estates is on the left. The diversion ditch cuts in front of the park (upper left to lower right) and goes into an area largely undeveloped on its way to the river (out of frame to the right).
Impact on River Grove Park
Once the Diversion Ditch passes through the area shown in the photo above, it enters wetlands and winds through River Grove Park. Two questions arise. How do we protect, from additional flow:
The park?
People downstream on the West Fork?
The first question is simple: split the flow in two. Take part through the undeveloped area west of the park. See the green below.
Green Line represents one possible route for diversion of the diversion ditch.
The second question is more complicated. We need a retention basin to hold the extra stormwater until the peak of any flood passes on the West Fork. But where? The closer you get to the river, the lower the elevation. Because of that, the basin could fill with floodwater from the river before it fills with floodwater from upstream. Fortunately, some large tracts of land exist on higher ground that could be purchased. HCFCD estimates the need at 1248 acre-feet. Preliminary engineering should start soon to address these issues.
Upstream Development Not Addressed by Analysis
Unfortunately the Kingwood Area Drainage Analysis did not address upstream development issues in Montgomery County. That was beyond the scope of work. Regardless, such issues must be addressed somehow, someday soon. Otherwise, even the improvements we invest in today could soon be overwhelmed by additional floodwaters.
In that sense, these channel improvements represent a stopgap measure. The real solution lies in making everyone in the region realize that we are all in this together.
The ten remaining channels/streams already offer a 100-year level of service. Therefore, no improvements are needed. HCFCD felt Taylor Gully should be the next priority after the Diversion Ditch. But the possible purchase of Woodridge Village may require re-thinking project requirements. Specifically, if Woodridge turns into a giant detention basin, the channel may not need as much deepening or widening.
Posted by Bob Rehak on 10/20/2020
1148 Days since Hurricane Harvey
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2020/10/RJR_4304.jpg?fit=1500%2C1000&ssl=110001500adminadmin2020-10-20 21:09:102020-10-21 09:32:19HCFCD Recommends Expanding Diversion Ditch as First Priority in Kingwood
The Harris County Flood Control District has released a Report Summary of results from the 600-page Kingwood Area Drainage Analysis. HCFCD will hold an online community meeting Tuesday night to discuss the results. It may help to review this summary or HCFCD’s before the meeting.
Objective: Protect Homes/Businesses from Bigger Rains
The objective of the Kingwood Area Drainage Analysis: to provide the knowledge needed to protect homes and businesses from flooding in a 100-year (1% chance) rain as defined by the new, higher Atlas-14 Rainfall Probability Statistics. Said another way, the engineers want to make sure that if you bought a home outside the 100-year flood plain, that you STILL won’t be flooded in a 100-year rain. Engineers call that “the 100-year Level of Service (LOS).”
Steams, ditches and channels evaluated as part of the Kingwood Area Drainage Analysis. Please note ditch numbers for any comments you make as the flood control district identifies them by that number.It will help communication.
What Study Included
To accomplish their objectives, engineers:
Evaluated historical floods and mapped flood damage
Created hydrologic and hydraulic models to quantify flooding risks along streams, channels and open ditches
Identified drainage issues associated with storm sewers and streets
Performed an overland flow analysis
Used LiDAR, record drawings, previous surveys and data collected in the field
Incorporated the impact of potential storm sewer improvements on channel capacity
Quantified detention capacity needed to prevent increasing flows into Lake Houston
Determined how many structures would benefit from each improvement (or planned future improvement)
Researched rights-of-way and flowage easements
Recommended channel-capacity improvements
Recommended bridge and culvert improvements
Developed preliminary cost estimates
Recommended construction sequencing
In places where ditches provide less than a 100-year level of service, storm sewers cannot empty into them during a 100-year rain. When that happens, water backs up into streets and can flood homes. So engineers are looking at the performance of the drainage system from end to end in conjunction with the City of Houston.
Limitations: What Study Does NOT Include
The study does NOT:
Include new topographic surveys
Evaluate improvements for greater than 100-year events
Examine Montgomery County issues except for North Park Drive
Identify sites for detention basins
Duplicate the San Jacinto River Basin Master Drainage Plan or associated sedimentation and sand trap studies
No construction is included as part of this project. This project will only lay the groundwork for subsequent construction projects.
Study Identified Nine Channels That Need Improvement
Not surprisingly, the Kingwood Area Drainage Analysis found that many channels do not need improvements. Said another way, they already provide the required level of service. However, engineers identified nine channels that DO need improvement to protect homes and businesses.
Six of those nine have rights-of-way controlled by HCFCD. They include:
For summary sheets of each recommended Kingwood Area Drainage Analysis project, click on the associated links. The Taylor Gully project will need to be re-analyzed if the Woodridge Village purchase goes through; that area could turn into a regional detention facility.
This table contains a summary of streams, channel types, ownership, current level of service, improvements, rights of way needed, cost estimates and detention estimates for all the projects considered in the Kingwood area.
Two Projects Recommended Immediately
Based on the results of the Kingwood Area Drainage Analysis, HCFCD recommends two projects: G103-38-00 (Kingwood Diversion Ditch) and G103-80-03.1B (Taylor Gully) move to the next phase: engineering design. Additionally, HCFCD recommends the Taylor Gully project be reanalyzed to determine how the use of Woodridge Village for detention could modify the recommended plan.
These two projects were chosen because:
They help the largest number of people.
HCFCD owns land to expand and deepen the Diversion Ditch.
Diversion Ditch enhancement will immediately take pressure off Ben’s Branch, and help flooding there.
Thus, these two projects address the three biggest needs. The remainder will have to wait for Capital Improvement funds.
First Step of Many
The Kingwood Area Drainage Analysis is a feasibility study that helped identify the problem areas. As you can see from the lifecycle diagram below, it represents the first step of several. The Flood Control District included $10 million in the bond fund (See F14) for Kingwood projects. That can be local-match seed money for attracting state and federal grants.
HCFCD will hold an online meeting Tuesday night. Engineers will describe the project and recommendations in more detail. You will also have a chance to interact with team members, make suggestions, and ask questions.
Or by phone at 855-925-2801 with Meeting Code: 9541
Please login a few minutes early. The Flood Control District has a brief survey on the login page that will help them track your concerns.
What the Flood Control District Needs from You
The Flood Control District needs to know about local issues that they may NOT have identified near you.
For example, culverts under Kingwood Drive for a ditch near me are almost totally blocked by sediment. That could have affected their analysis. And the stream may have correctable issues that could easily prevent future flooding.
Another example. The recommendations include taking out the low water crossing near Bear Branch Elementary School. Many kids use that to walk or bicycle to school. Removal without replacement would create a major inconvenience. It might also negatively affect downstream bridges damaged in previous storms.
A final example: the study did not recommend any changes to the bridge over Taylor Gully at Rustling Elms. However, many Elm Grove residents identified that as a major issue in two floods last year.
The Rustling Elms Bridge is a road over twin culverts, not a true open bridge like the one farther downstream in the background.
Please join the meeting Tuesday night and be prepared to discuss such issues. Volunteer your local knowledge. Speak up now or live with the results.
Credits
The Kingwood Area Drainage analysis cost $700,000. Funds from the 2018 Harris County Flood Bond and TIRZ 10 paid for this study.
Posted by Bob Rehak on 10/19/2020
1147 Days since Hurricane Harvey
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2020/10/hvr7ksjet8llq3oonj3l.jpeg?fit=1599%2C1188&ssl=111881599adminadmin2020-10-19 16:50:002020-10-20 20:26:12Sneak Peak at Results of Kingwood Area Drainage Analysis; Review Before Meeting Tuesday Night
