In the afternoon of 1/27/22, Harris County Flood Control District (HCFCD) contractor Sprint Sand & Clay began excavation of additional detention pond capacity on Woodridge Village. Woodridge is the former Perry Homes property implicated in the flooding of Elm Grove Village and North Kingwood Forest twice in 2019. Numerous factors contributed to the flooding. But insufficient detention pond capacity led the pack. The volume excavated by Perry contractors fell about 40% short of Atlas-14 requirements.
Initial Work Will Improve Access
The initial work will improve access to the site. Sprint says it hopes to begin excavation in earnest next week. By comparing the picture and map below, you can see that the task will be immense.
Looking NE at main portion of Woodridge Village Site as excavation of new detention pond begins. It will extend to the pond in the upper right.Excavation off the green area above will more than double the detention pond capacity on the Woodridge Village Site.
History of Project and Contract Details
In February last year, HCFCD purchased Woodridge Village with the intention of creating additional detention pond capacity. Fast forward to November 2021. HCFCD and Sprint signed an E&R contract. E&R stands for Excavation and Removal. Under the terms of their contract, Sprint Sand & Clay will excavate material as needed.
Taxpayers generally like E&R contracts, but anxious homeowners may worry about the “as needed” clause. That can slow work down if market demand falters. Nevertheless, Sprint has an obligation to remove at least 5,000 cubic yards a month. That’s enough to fill 500 dump trucks. In total, they’ll fill 50,000 before the job is done.
Covid Delayed Start
The project could have started in December, but Covid-related absences slowed the contractor. This afternoon, however, the contractor began a) clearing an access road for trucks into the site and b) clearing space for a construction trailer near the excavation. The contractor hopes to begin excavation in earnest next week. But again, they make no guarantees on that point.
Pictures Taken 1/27/22
Regardless, signs of progress are welcome. Here are pictures taken of the project just hours into it.
Sprint began by clearing a two-lane road for their trucks opposite the entrance to the Northpark Recreation Area on Woodland Hills Drive. The company plans to work around the high school’s schedule (upper right).The company began by clearing an area near the entrance to the largest portion of the site.Dirt from the initial excavation is being stockpiled near the Woodland Hills entrance opposite Kingwood Park High School for the moment.
The contractor appears to be shuttling dirt from the excavation area toward the entrance. It’s not immediately clear whether that dirt will be used to build up a construction road or hauled offsite.
Posted by Bob Rehak on 1/27/2022
1612 Days since Hurricane Harvey
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2022/01/20220127-DJI_0534.jpg?fit=1200%2C799&ssl=17991200adminadmin2022-01-27 17:24:592022-01-27 17:26:50More Woodridge Village Excavation Started Today
US Fish & Wildlife Map Shows Wetlands Dot Development
From US Fish & Wildlife Service National Wetlands Inventory. Madera will stretch past the left/right edges of this picture north of SH242 (the east/west highway near bottom.) FM1314 bisects picture from N to S in middle.
FEMA’s Base Flood Elevation Viewer Shows Flood Risk
Note that this survey shows only about a quarter of Madera (see below). The survey stops abruptly on the western margin. So, it is hard to say with certainty how bad flooding is throughout the rest of the site.
Yellow outline shows approximate outline of FEMA BFE survey shown above within Madera tract(black/white outline).
Option to See Depth of 100-Year Flood Waters
Also note that the purple area shows only the extent of 100- and 10-year floods. However, within the FEMA BFE viewer, you also have the option to select a layer that illustrates the depth of 100-year floodwaters. See below. (FEMA does not offer the option to show the depth of 10-year floods.)
FEMA’s estimated Base Flood Elevation Viewer showing extent of 100-year flood on left and depth on right.
Limitations of BFE Viewer
Of course, FEMA shows “estimated conditions” before developers bring in fill and alter drainage. But notice how a pre-existing development near Madera would fare in the same 100-year flood. You can see the close up below just above SH242 near the right edge of the image above.
FEMA shows that most homes in this development are still in the flood zone and would still flood to a depth of 1-2 feet in a hundred-year flood.
The street leading out of the development to SH242 could be under more than FIVE FEET of water in places!
FEMA Base flood Elevation Viewer
FEMA’s “Estimated Base Flood Elevation” is “The estimated elevation of flood water during the 1% annual chance storm event.” Structures below the estimated water surface elevation may experience flooding.” A 1%-annual-chance flood is also known as a 100-year flood. FEMA defines properties with a 1% annual chance of flooding as having “high flood risk” and says they have a 26% chance of flooding during the life of a 30-year mortgage.
Purposes of BFE Viewer
The agency developed its Base Flood Elevation viewer with several purposes in mind. To:
Inform personal risk decisions related to the purchase of flood insurance and coverage levels.
Inform local and individual building and construction approaches.
Prepare local risk assessments, Hazard Mitigation Plans, Land Use Plans, etc.
Provide information for “Letter of Map Amendment” (LOMA) submittals.
A LOMA lets the developer of a subdivision change the depiction of how flooding affects his/her subdivision. It’s the key to offering up-to-date risk assessments.
Full BFE Reports Available
FEMA also lets you download or print full BFE reports that give more specific estimates of flood depth at exact points, not just within a wide area.
FEMA’s BFE Viewer also gives you the option to print out a detailed flood-risk report by clicking on a point.
At the point shown above, you could expect 4.2 feet of water above the land surface in a 1%-chance flood. For the full report, click here.
Here’s what that point looked like last Saturday (1/22/22) from the air.
Madera development today at FM1314 and SH242, the point shown in BFE report above.
Cross-check this area on the maps above for wetlands and swamps! Then you can see why it’s so soupy.
BFE, Fill Not Mentioned in Drainage Analysis or Construction Plans
Text searches of Madera’s construction and drainage plans showed no references to “BFE” or “base flood.”
It seems unlikely that a “cut and fill” operation could excavate enough dirt from Madera’s drainage channel (dotted blue line with red parallel lines) and detention ponds to raise the whole site out the hundred-year flood zone. Five feet is a lot of fill for a 1700 acre site.
To raise a site this large, contractors would likely have to bring in fill from outside the property. But a text search from the word “fill” did not turn up any exact matches either.
So maybe they’re just planning to create the world’s biggest drain and hope to carry water off before it can reach homes.
However, a summary of the Madera master drainage plan notes…
“Coordination with MCED [Montgomery County Engineering Department] andadjacent property owners is recommended … on the potential need for inundation easements.”
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/2022/01/20220125-Screen-Shot-2022-01-25-at-3.52.07-PM.jpg?fit=1200%2C600&ssl=16001200adminadmin2022-01-27 06:08:242022-01-27 06:22:32New MoCo Development Being Built on Wetlands in 10-Year Flood Zone
Yesterday, 1/25/22, Harris County Commissioners Court named Dr. Christina Petersen as the new head of the Flood Control District. That position had been open for seven months since Russ Poppe resigned last July. Below is a brief bio of Petersen distributed by David Berry, the new Harris County administrator.
Dr. Christina Petersen, new head of Harris County Flood Control District
Petersen Background
“Dr. Christina “Tina” Petersen will serve as the first female Director of the Flood Control District in its 85-year history. She joins Harris County from the Harris-Galveston Subsidence District, where she has served as Deputy General Manager for the past 3 years and oversaw the District’s Regulatory Planning, Scientific Research, and Water Conservation Programs. She earned her Bachelor’s degree in Biology and Environmental Studies from Baylor University and her Master’s and doctoral degrees in Environmental Engineering from the University of Houston. She is a registered Professional Engineer in Texas and has over 15 years of experience working with local city governments as well as water authorities, State agencies, and cities across Texas to deliver complex water supply and water quality projects.”
I’m trying to learn more about Dr. Petersen’s background. What I didn’t see in this was any mention of hydrology experience. Nor did I see any mention of private-sector experience. More news to follow.
Other Related Appointments
Meanwhile, Berry’s press release also listed:
Dr. Milton Rahman, who will serve as the new County Engineer. Dr. Rahman is a Professional Engineer, Project Management Professional, and Certified Floodplain Manager.
Lisa Lin, the first director of the Sustainability for Harris County.
Daniel Ramos, the new Executive Director of the Office of Management and Budget.
Posted by Bob Rehak based on a press release by Dave Berry, Harris County Administrator
1611 Days since Hurricane Harvey
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2022/01/Tina-Petersen.jpg?fit=468%2C624&ssl=1624468adminadmin2022-01-26 12:01:582022-01-26 13:27:08Harris County Names Dr. Tina Petersen New Head of Flood Control District
When it comes to flood control in Harris County, you often hear claims of “historic disinvestment” in low-to-moderate income (LMI) neighborhoods. Residents allege that they flood because Harris County Flood Control District (HCFCD) funneled dollars into affluent neighborhoods for decades while ignoring lower-income watersheds. But are those claims true? Not if you look at the numbers since 2000.
What Data Shows
See the table below. I compiled it from data supplied by HCFCD in response to a Freedom of Information Act (FOIA) Request. The table ranks each watershed in the county by its percentage of LMI residents. It also breaks them into two groups – those with percentages of LMI residents above and below 50%.
HCFCD Spending by Watershed since 2000through the end of Q3, 2021.
Harris County has 23 watersheds.
Column 1 shows the watersheds broken into two groups – those with more or less than 50% LMI residents.
Column 2 shows the percentage of LMI residents in the watershed. Those with the highest percentages of low-income residents are the least affluent.
Column 3 shows the historic investment in flood mitigation between 2000 and the end of the third-quarter 2021.
Column 4 shows the historic investment plus inflation compounded annually.
Column 5 shows the percentage of inflation over time.
No Historic Disinvestment
In raw dollars, the eight least affluent watersheds received 61% of all dollars since 2000. Fifteen more affluent watersheds received only 39%.
The 8 less-affluent watersheds received $700 million more than the other 15!
After accounting for inflation, the eight low-to-moderate income watersheds received on average almost $300 million each. The rest received only about $90 million each.
Notice also how the rates of inflation tend to be much higher in the less affluent group. That’s because HCFCD has been spending more money in these watersheds over a longer period of time. For example: If a watershed received a $10 million project in 2000, more inflation would apply than if the investment was made yesterday.
Conclusion: I see no pattern of historic disinvestment in low-to-moderate income neighborhoods by HCFCD.
Funding Flows to Damage
The reality of flood bond spending is far more nuanced than most people have the time or desire to explore. At a high level, though, funding flows to damage.
Older neighborhoods inside the Beltway have higher flood risk because of older development regulations, older building codes, and storm sewers or ditches that have filled in with silt or vegetation. See pictures below from Halls Bayou.
Blocked street drains that turn neighborhoods into detention ponds.
The people in this neighborhood (Halls Bayou) claim they “flood every time.” But if you look at historical gage data, you will see that Halls came out of its banks at Tidwell only twice in the last 20 years – once during Harvey and once during Imelda. Harvey was bad. During Imelda, the bayou overtopped banks only by a foot.
I conclude that repeat flooding in the neighborhood shown above comes from blocked street ditches. They turn neighborhoods into giant detention ponds. But the ditches are the responsibility of Precinct Commissioners, not HCFCD.
To sum up, I do not see a pattern of historic disinvestment by HCFCD in Harris County’s LMI neighborhoods.
Posted by Bob Rehak on 1/25/2022
1610 Days since Hurricane Harvey
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2022/01/Screen-Shot-2022-01-25-at-7.07.51-AM.png?fit=758%2C1060&ssl=11060758adminadmin2022-01-25 11:27:132022-01-25 11:37:35Myth Buster: Historic Disinvestment in LMI Watersheds?
Zeve joined HCFCD one day after the Halloween Flood of 2015. He had a distinguished career in the private sector that led from Bachelors and Masters degrees in civil engineering at Texas A&M to one of the most important flood-control jobs in the country. Along the way, Zeve proved himself to be an accomplished engineer, a top-notch manager, a driven public servant, and a consummate communicator who handled himself with grace under pressure – all while managing the equivalent of a $5 billion startup in little more than three years. Like most good managers, Zeve shuns the spotlight, preferring to credit his talented team of employees and consultants.
Regardless, Zeve helped organize and lead the effort to build a $2.5 billion flood-bond program after Hurricane Harvey in 2017. He led 21 of 23 watershed meetings leading up to the bond referendum, which voters approved by 86%.
But $2.5 billion was just the bond money approved by voters. With projected matching funds, the total value exceeded $5 billion.
Imagine losing the Chief Operating Officer of a $5 billion startup! The picture that comes to mind is that of a juggler with 180 balls in the air.
That’s how many projects Flood Control employees, consultants and contractors currently have in the works.
Zeve oversaw the transition of HCFCD from a sleepy County department that delivered about $30 million of capital improvements per year to one that delivers more than $400 million per year. That required internal process improvements, new hires, staff augmentation, implementation of new management software and more.
It also required a change in culture. The cultural shift that Russ Poppe and Matt Zeve brought to the Flood Control District produced a sense of urgency in all projects. It was based on the fact that somewhere in Harris County, it could flood tomorrow.
Zeve also led efforts to revamp how HCFCD communicates with the public, stakeholders and elected officials. The result: one of the most open and transparent government departments anywhere.
Delivering Under Pressure
He did all this under pressure that could be likened to wartime. Harris County experienced four 500-year storms from 2015 to 2019. During Harvey, an estimated 154,170 homes flooded across the county. Two thirds were outside the 100-year floodplain and did not have flood insurance. Harvey ranked as the heaviest rainfall event in North American history. Families, their life savings and whole communities were devastated.
At a time of crisis when most people would have headed to the exits, Zeve stepped up to the plate for the citizens of Harris County. To this day, he and his team are virtually the only ones in Harris County actually moving dirt to mitigate flooding.
Despite the Flood Control District’s progress, trying to serve 4.7 million people with PTSD would have challenged anyone. A few vocal people in densely-populated, low-to-moderate income neighborhoods felt they were not getting enough dollars from the flood bond. In reality, they were already receiving the lion’s share. Regardless, this vocal minority now seems to be dictating Commissioners Court policy.
When Politics Undermines Performance…
In this constant, contentious political tug-of-war, I’m sure Zeve often felt he had a thankless, 24/7 job. That had to weigh heavily on his decision to leave. Now that he’s leaving, those ignorant of his contributions and funding realities may give thanks, but the rest of the county should be alarmed.
People whom I speak with regularly tell me that the Flood Control District staff is devastated that Zeve is leaving; he was well-liked and respected. Staff are openly wondering why Commissioners Court would allow strong leaders like Russ Poppe and Matt Zeve to leave. I wonder as well. What is their end game?
Perhaps Court members want their own appointees instead of qualified and dedicated staff members. Maybe they value political persuasion over performance and protecting residents.
We will most likely never know. One could conclude that the majority on Commissioners Court may not care as much about flood mitigation as its members claim.
What Next?
Zeve’s team has more than 180 bond projects currently underway. And it could take months to find a new Deputy Executive Director. Commissioners Court still has not found a suitable replacement for Russ Poppe seven months after he resigned.
Zeve is just the latest in a long line of Harris County department leaders driven to departure for no good reason. His loss will leave a department dismayed, distracted and demoralized. Could anyone blame employees for wondering what thanks await their loyalty and hard work?
Posted by Bob Rehak on 1/24/2022
1609 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/2018/09/MattZeve_headshot-e1536349273560.jpg?fit=900%2C1175&ssl=11175900adminadmin2022-01-24 09:23:262024-04-20 19:45:58Matt Zeve Resigns from Harris County Flood Control District
Correction: Original plans called this development Madera. Subsequently, the developer named it Mavera. I have changed all mentions of the former to the latter because of confusion it caused as time went by.
A new 1700-acre development called Mavera at FM1314 and SH242 claims it will have “no adverse impact” on surrounding areas. However, to determine this, the authors of the drainage impact analysis used a controversial technique permitted by Montgomery County drainage regulations. It’s called “hydrologic timing.” The technique doesn’t take into account drainage from other developments in surrounding areas. Nor did it factor in the destruction of wetlands.
Outline of Mavera Development (dotted line) just north of SH242 at FM1314). For reference, Artavia (mentioned below) lies under the legend.
The Problem with Hydrologic Timing
The theory behind hydrologic timing is that if you can get your water to the river before the peak of a flood arrives, then you aren’t adding to the peak. This might have “no adverse impact” if you were the only development in a watershed. But when you’re:
Artavia, for instance, claimed that its drainage plan would get water to the West Fork 35 hours before upstream peaks arrived. Meanwhile, Mavera (literally a few hundred feet away on the other side of SH242), claims it will get its peak to Crystal Creek 28 hours before that stream’s peak arrives. Crystal Creek empties into the West Fork just upstream from Artavia’s drainage.
Natural and man-made peaks for 100-year storm on left. Engineers will get water to creek twice as fast as nature.
So you could have potentially one peak on top of another and another, etc.
Neither development accounts for peak changes induced by the other in analyses.
Now multiply that times a hundred or a thousand developments and you see the danger.
As far as I can see, the drainage impact analysis supplied by engineers makes no attempt to compare the amount of natural detention to man-made detention.
When Does Real Peak Happen and Why Does It Matter?
Engineers claim they aren’t adding to discharge; they’re just shifting the peak. But because of all the development in MoCo in the last 40 years, it’s not clear when that peak from outside the development will really happen.
In fairness, Mavera plans do show a number of detention ponds. But even with those, Mavera will still add 16,300 cubic feet per second to the West Fork in a 100-year storm. And that’s just for Phase 1 of the development! That’s why engineers say below, “will not likely have an impact on peak flows…”
From documentation supplied to MoCo engineer’s office by Torres & Associates on 2/19/21
To put that volume in perspective, during the peak of Harvey, the SJRA says the nearby West Fork carried 115,000 CFS. So Mavera will contribute 14% of Harvey’s volume at that point on the West Fork. And most people consider Harvey far more than a 100-year storm.
Problem with Higher Peaks
The hydrograph below shows how the peak on Brays Bayou shifted over time with upstream development. On the West Fork, this may already be happening.
Time of accumulation in Brays Bayou was cut in half over time, leading to higher flood peaks.From HCFCD, FEMA and Tropical Storm Allison Recovery Project.
In the last 20 years, HCFCD and its partners have spent more than $700 million on flood mitigation in the Brays Bayou watershed.
The safest strategy is for new developments to “retain their rain” until the peak of a flood has passed and then release it slowly. “Retain Your Rain” is the motto of most floodplain managers. If everyone did that, there would really be “no adverse impact.”
Delaying stormwater discharges, not accelerating them, is the safest strategy.
Faster Runoff, Faster Erosion
As stormwater approaches Crystal Creek, it will encounter a steep drop that requires the use of check dams and other measures to slow water down.
Mavera runoff as it approaches Crystal Creek (left) encounters a drop that could increase erosion if not mitigated properly.
Wetlands no more. Looking east from over FM1314. Area in upper left has not yet been cleared but will be.
Land Consists Primarily of Wetlands
The hundreds of pages supplied by the Montgomery County Engineer’s Office in response to a FOIA Request show that this development tract consists “…primarily of evergreen and mixed forest and woody/herbaceous wetlands.” [Empasis added.] Yet the drainage analysis never again mentions that when it claims the development will have no adverse impact.
Looking west toward FM1314, which runs through middle of frame and US242 (upper left) Note drainage and clearing activities moving west. Area in upper right will also eventually be cleared. Note West Fork San Jacinto beyond SH242.Looking north across drainage ditch. that bisects development (see below). Many of those trees will soon be gone. The northern half of the subdivision will look like the cleared area in the foreground.Building homes over a swamp can lead to foundation shifting and cracking. Drainage from the eastern half of Mavera will flow through the concrete box culverts under FM1314 to the western half.Looking west. Note standing water in forest between ditch and SH242 (out of frame on left).Western half of development is now in initial clearing phase.Map of development showing location of drainage ditch, Crystal Creek and San Jacinto (lower left). Virtually all cleared areas to date are below the blue dotted line which represents the drainage ditch. Area below the drainage ditch appears to represent less than half of the total area.
HCFCD Position on Hydrologic Timing
Harris County Flood Control has long lobbied to eliminate hydrologic timing in drainage analyses for the reasons mentioned above. However, Montgomery County Commissioners have not acted on the proposal.
Posted by Bob Rehak on 1/23/2022
1608 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/2022/01/20220122-DJI_0513.jpg?fit=1200%2C799&ssl=17991200adminadmin2022-01-23 17:24:002025-08-19 22:20:20New 1700-Acre MoCo Development Claims “No Adverse Impact,” But Doesn’t Study Other Areas
Almost half the watersheds in Harris County originate in surrounding counties.
Ten of 23 Harris County watersheds originate outside the county.
If upstream communities do not implement regulations that help prevent flooding, downstream communities will face increased flood risk regardless of how much money they spend on flood mitigation.
Loopholes and Omissions in Regs that Increase Flooding
In my research, I’ve discovered loopholes or omissions in regulations that, if addressed, could help reduce flooding. These will be controversial. But they deserve debate.
Maintain ditches. Get surrounding counties to maintain ditches, i.e., HCFCD. Many don’t have organizations to do that. Some even give adjoining property owners the responsibility – something clearly beyond their capability. We also need to create dedicated funding streams for maintenance that cannot be diverted. Finally, create an online map that shows what maintenance will happen when and where, so citizens can report problems when they see them.
Follow the Association of State Floodplain Managers’ recommendations for documenting “No Adverse Impact” in drainage studies. They’re more stringent than most local regs. They address topics such as water quality, erosion and sedimentation, not just water levels.
Analyze “depressions lost” through development, i.e., ponds.Require mitigation of that lost detention capacity. Again, since most counties do not require permits or inspections for clearing and grading land, there’s often no way to account for these in drainage impact analyses.
Make factors in flood studies such as Manning’s Roughness Coeffcients and soil curve numbers less subjective.Require engineering documents to show how coefficients were selected. Establish minimum values that force developers to plan for worst case scenarios. Require a sensitivity analysis that prohibits fudging the numbers.
Encourage the use of nature-based flood mitigation, i.e., bio-swales and the use of vegetation in ponds that encourages infiltration. The Corps, ASFPM and FEMA already do this.
Break up counties into at least four Atlas-14 zones.Montgomery County uses one average for the entire county. But an average increases costs on areas that receive less rain than the average rainfall. It also increases risks in areas that receive more than the average.
Include “erosion” when proving “No Adverse Impact“. Require field visits that document pre-existing erosion. Developers must ensure they will not increase erosion potential and that and no new erosion areas will be created. Erosion increases sediment build up that can decrease conveyance downstream. It also decreases water quality and maintenance intervals; and increases mitigation costs such as dredging. ASFPM says, “An adverse impact can be measured by an increase in flood stages, flood velocity, flows, the potential for erosion and sedimentation, degradation of water quality, or increased cost of public services.”
Adopt new post-Harvey flood maps. Some areas have fought Allison maps for 15 years. Other areas still base their maps on data from the 1980s. This benefits builders and harms buyers. People don’t see their true flood risk. Commissioners sometimes fight updates because they fear it will harm growth.
No matter how much money we spend on flood mitigation, if the amount of inbound water constantly increases, we won’t reduce flooding. It’s like trying to go up the down escalator.
But what’s in it for upstream communities? The answer is simple. Many are already starting to flood. Everybody lives downstream from somebody else. Without common sense flood regulations, even those that aren’t flooding yet will flood soon enough. This isn’t about increasing costs, though some will argue that. It’s about self-preservation.
Posted by Bob Rehak on 1/22/2022
1607 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/2022/01/image.png?fit=868%2C686&ssl=1686868adminadmin2022-01-22 11:20:322022-01-22 11:36:00Opportunities for Improvement In Flood Regulations
New developments in many jurisdictions must demonstrate “No Adverse Impact” (NAI) in drainage studies before they can get construction permits. City and county engineers want to know the development won’t harm others before they approve plans. But what does “No Adverse Impact” really mean? It depends on the jurisdiction.
Meaning Varies
Most jurisdictions require that new developments won’t add to flooding. In Montgomery County, for instance, developers do this by comparing runoff pre- and post-development. If engineers can show that post-development runoff does not exceed pre-development runoff, then they get their permit.
Such studies focus primarily on water surface elevations. But the Association of State Floodplain Managers (ASFPM) has a much broader definition.
In their book, No Adverse Impact means that actions of any community or property owner, public or private, “should not adversely impact the property and rights of others.”
An adverse impact can be measured by an increase in flood stages, flood velocity, flows, the potential for erosion and sedimentation, degradation of water quality, or increased cost of public services.
ASFPM
Definition Should Apply Beyond Floodplain
According to ASFPM, “No Adverse Impact” floodplain management extends beyond the floodplain to include managing development in the watersheds where floodwaters originate. NAI does not mean no development. It means that any adverse impact caused by a project must be mitigated, preferably as provided for in the community or watershed-based plan.
Flood losses are increasing by $6 billion annually. That’s because current policies promote intensification in high risk areas. They ignore changing conditions, undervalue natural floodplain functions, and often ignore adverse impacts.
Even if we perfectly implemented current standards, damage will increase.
Floodplains change due to filling.
Current regulations deal primarily with how to build in a floodplain vs. how to minimize future damages.
NAI actually broadens property rights by protecting those adversely impacted by others.
Trends in case law show that Act of God defenses have been greatly reduced due to ability to predict hazards events.
Hydraulic models facilitate proof of causation.
Use of sovereign immunity has been greatly reduced in lawsuits.
Communities are most likely to be held liable not when they deny a permit, but when they permit a development that causes damage to others.
NOAA’s Atlas-14 rainfall probabilities for this area show that’s about a 5-year rain.
NOAA’s Atlas-14 Rainfall Probability standards for the Lake Houston Area.
But rising floodwaters cut off large parts of Plum Grove – including escape routes. The new elevated City Hall nearly flooded again even though it’s far above the 100-year floodplain.
Photo from evening of 1/8/2022 courtesy of Plum Grove VFD after about six inches of rain.
As far as I can tell, 2004 Liberty County Subdivision Rules do not require “no adverse impact” for new developments. However, they do stipulate that “All roads and streets shall be designed to convey a 10-year storm event and not more than 6″ of water over the road in a 100-year storm event.”
Looks like the engineers missed all of those targets! This is a good example of why all jurisdictions should specify No Adverse Impact in their drainage regulations.
Posted by Bob Rehak on 1/20/22
1605 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/2020/12/20201207-Aerial-Dec-2020_851.jpg?fit=1200%2C800&ssl=18001200adminadmin2022-01-20 22:38:032022-01-21 09:09:20What Does “No Adverse Impact” Really Mean in Drainage Studies?
This proposal attempts to establish new rules for the Equity Prioritization Framework adopted by commissioners in 2019 and changed several times since. These new rules were provided to Task Force members only within the last few days even though the document is dated December 14, 2021, more than a month ago.
The rule changes apply mostly to the distribution of Trust Fund money established to supplement the flood bond if partner funding did not materialize as expected. However, the proposed changes could affect the distribution of flood bond funds that voters approved by 86% in 2018.
Proposal #1:
Place more emphasis on number of people, using structures as a proxy for people. Benefit = efficiency.
Observation:
This may disadvantage LMI neighborhoods as those projects tend to cost more and the neighborhoods have more apartments. They also have large numbers of homes crowding channels and floodplains. So, buyout costs will be higher. And historically, buyouts cost almost as much as construction. Also, apartments cost far more than single family homes. We need time to look at data on this.
Proposal #2:
Potential partner funding should not be considered in prioritization for use of trust funds.
Observation:
What if you could make trust fund dollars go nine times further? Typically, HUD grants require only a 10% match.
Proposal #3:
Use trust funds for projects, like street flooding, not even mentioned in the bond.
Observations:
The County proposes using FEMA damage data back to 1977 to determine “Existing Level of Service.” This is a blatant attempt to tilt the playing field toward the inner city. In 1977, Beltway 8 and Intercontinental airport were still under construction. US59 was a 2-lane blacktop road. Outlying neighborhoods like Kingwood barely existed. This makes it impossible for any outlying neighborhoods to qualify for help with Trust Funds.
Choosing 1977 as the starting point ignores 45 years of flood mitigation spending totaling approximately $5 billion.
We don’t have enough money in the trust fund to complete all the bond projects. So, if we spend trust fund money on projects not in the bond – without partner help – it will mean cancelling bond projects somewhere else.
Implementing this proposal will make it very difficult to get voters to approve future flood bonds.
Street flooding is often caused by blocked drains. Rains can’t get to channels and streams. Fixing ditches has historically been the job of cities and precincts. HCFCD funds have focused on channels and streams. Street ditches were never mentioned in the bond.
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2022/01/MultiBlockages.jpg?fit=1440%2C960&ssl=19601440adminadmin2022-01-19 10:46:072022-01-19 16:01:41Harris County Making Another Attempt to Shift Flood Mitigation Funds
Lakewood Cove residents reported yesterday and today that contractors at the Laurel Springs RV Resort are pumping stormwater from their detention pond into Precinct 4’s Edgewater Park. The reports are true. And it’s a permit violation.
I also found contractors bringing in fill from the outside that I thought was going to be “cut” from the detention pond. All photos below were taken on 1/18/22.
Pumping From Pond onto Neighboring Property
The approved permit plans clearly state that “Stormwater runoff shall not cross property lines.”
Stamp on many pages of approved Laurel Springs RV Resort plans.
I guess at some point the water in the pond ceased being runoff. Now it’s just a nuisance. The plans said pond water would be pumped into the City storm sewers. Hmmmm.
Photographed from Laurel Springs Lane looking west.
Here’s an aerial photo looking toward Laurel Springs Lane.
Check out all the muck being washed into the woods. Those woods belong to Harris County Pct. 4. That’s part of new Edgewater Park.
Note the lack of silt fences in the two photos above. Plans clearly state that silt fences will be installed to keep silt from escaping the property. Double Hmmmm!
Bringing in Fill instead of Moving It From Within the Site
As I photographed the pumping, I noticed a parade of dump trucks bringing in fill, dumping it, and leaving as a bulldozer spread it out and another machine quickly compacted it.
Looking NW toward Lowes in top center. Note dump truck depositing fill – one of many that I watched.The area where they deposited fill just north of the pond corresponds to the plans. See below.
From text on the image above, I assumed that the job was to be a routine “cut and fill” operation. Maybe I shouldn’t have assumed.
Cut and Fill is an industry standard in floodplains. It means you move dirt from one part of the site to another. So, there is no additional fill brought into the floodplain. The fill area above appears to be in the .2% annual chance floodplain, according to the old FEMA map below. However, the developer did not mark the .2% chance floodplain on plans.
FEMA floodplain map. Aqua = 1% annual chance. Brown = .2% annual chance.It appears the northern part of the detention pond (not shown on this old satellite image) cuts between the aqua and brown areas.
For the record, Chapter 19 of Houston’s Code of Ordinances currently does not prohibit bringing fill into the .2% annual chance floodplain. See Section 19.34.
Posted by Bob Rehak on 1/18/2022
1603 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/2022/01/20220118-DJI_0490.jpg?fit=1200%2C799&ssl=17991200adminadmin2022-01-18 20:33:432022-01-18 20:40:31RV Resort Pumping Stormwater Into Edgewater Park, Bringing in Fill
