Erosion can sometimes be sudden. It’s not always a slow process of water grinding away at dirt and dissolving it, or wearing down rocks. This post will examine several examples around us and look at their implications. I intend it as a continuation of yesterday’s post about ditch maintenance.
Hydraulic action – When rapidly moving water churns against river banks and scours or undermines them.
Abrasion – Caused by small pebbles moving along a river bank or bed and knocking other particles loose. Think of sandpaper.
Attrition – When rocks carried by the river knock against each other. They break apart to become smaller and more rounded. This is how boulders turn into gravel.
Solution – When water dissolves certain types of rocks, for example limestone. We often see this in Florida, where sinkholes frequently develop.
Most of these processes happen slowly. But the first can be sudden. One storm. One flood. And boom. That river bank where you used to sit and quietly contemplate nature is gone.
Now You See It; Now You Don’t
Sometimes large slabs of a river bank or ditch suddenly slump into a river, almost like mini landslides. One flood expert commented on the picture above; he said “The owners of those new homes may suddenly find the ditch in their backyards.”
At other times, the size of a flood forces a river to widen. We saw this during Harvey and Imelda. The relentless pounding of flood waters carries away everything in their path. Cutbanks (the outside of a river bend) are especially vulnerable. Water slams directly into them like a firehose and washes them away. This action actually changes the course of a river over time.
Most of the time, it happens so slowly, we barely notice it. But during large floods, it’s sometimes sudden, large, and devastating to homeowners or businesses near rivers.
Three More Examples of Hydraulic Action
Example A: East End Park
Example B: Balcom House and River Migration
Example C: River Aggregate Mine on West Fork in Porter
The third example comes from the abandoned River Aggregates sand mine beyond the new development in the first picture above. It’s a spectacular example of river migration.
Wait a minute, you say! What happened to the pond. After the river bank collapsed, the pond drained, exposing sediment already within it. And the action of draining concentrated more sediment in it, like all the remnants of food trapped in your sink drain after you’re done washing dishes.
History of Pond
The missing, shallow pond in the foreground above used to be the settling pond for River Aggregates.
Here’s how it looks today from a helicopter.
Lessons of Life Near a River
Most people never live long enough to see massive changes such as these in rivers. In most places, river change happens on a geologic time scale. But along the Gulf Coast, hurricanes can create floods that make rivers change on a human time scale, as these examples have shown.
What can we deduce from this?
Around here, we need to give rivers room to roam. Parks, green spaces, and golf courses, often represent the highest and best use of land near a river, bayou or ditch.
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/2019/10/EastForkByBoat_115.jpg?fit=1280%2C854&ssl=18541280adminadmin2020-05-18 09:09:122020-05-18 09:39:26Erosion: Sometimes Sudden
In a meeting today, the Houston Planning Commission deferred automatic approval of the general plan for Orchard Seeded Ranches by taking the item off the consent agenda. The Commission then asked the developer to consult with the City Engineer; the Planning and Development Department; and Harris County Flood Control before bringing further requests back to the Commission.
Taking the item off today’s consent agenda should send a strong signal to the developer that rough waters lie ahead. Any proposal will likely be debated publicly when/if the developer returns.
For orientation, the developed area in the middle is the Barrington. The line down the west side is Woodland Hills Drive. And the river at the bottom is the West Fork.
Filing a “general plan” like this is the first step in developing property. The developer has not yet submitted detailed plats showing construction details.
Virtually Entire Development in Floodway or Floodplain
About half of the Orchard Seeded Ranches lies in the floodway of the San Jacinto West Fork. FEMA defines floodways as the main current of a river during a flood. In the map below, that includes everything beneath the red line.
Virtually all of the purple area above the red line lies in the floodplain. FEMA defines a floodplain as “storage” for water during a flood. That means water covers the land without moving rapidly.
I created the map above by combining the area to be developed with the FEMA flood map below.
Wetlands Issues Also Abound
Every part of the proposed development contains wetlands to some extent.
US Fish and Wildlife documented another eagle’s nest on the developer’s property. And the Balcom family, which lives near the western edge of the developer’s property, regularly photographs eagles from their balcony.
What’s in a Name
The name sounds as if the development would be lower density than the 50-story high-rises previously planned. But you never know. In the development business, names often have more evocative than literal significance. Look at the Houston Heights. Bridgeland (on the prairie). Mount Houston. You get the idea.
Whatever the development is, when and if the developer returns to the Planning Commission, we should not forget that:
When floodplain maps are redrawn using Atlas-14 data, that floodway will likely expand significantly.
A Less Risky, Less Costly Alternative
All of these factors will increase the risk and cost of any development.
The safest, sanest course for the developer – before putting more money at risk –would be to meet with community representatives about:
Purchasing this land
Putting a conservation easement on it
Letting it revert to nature and turning it into park land
Harris County Flood Control District has $175 million allocated in the flood bond for partnership projects with “Municipalities, Authorities, and Other Districts in Harris County.” See item Z100-00-00-MUNI.
That money could help purchase such property and turn it into green space forever. KSA, the Lake Houston Chamber, civic leaders and residents should get behind that idea. Judging by the response to Romerica’s last offering, it’s clear that residents would much rather see this area turned into parks than see the San Jacinto turn it into blight.
Jim and Melissa Balcom live in a spectacular three-story home built on pylons 12 feet above the ground and 20 feet above the San Jacinto West Fork. Their home fronts on the north bank immediately west of River Grove Park. They named one son River, another Talon (like the eagles that perch outside their windows), and their dog Rio. To say they love the river lifestyle would be an understatement. But they admit it comes with a high level of anxiety. Jim, who is a contractor, built the house himself on property that Melissa’s father owned for decades. Jim wrangled with the City of Houston and FEMA for TWO YEARS over permits.
Their home now sits about 125 feet from the West Fork. Before Harvey, it was 300 feet. The flood eroded a peninsula and small channel between them and the river. The peninsula used to have a thick stand of trees on it. They’re all gone now. Harvey gave the Balcoms a spectacular view, but it also gave them a constant reminder of the river’s terrifying power.
I interviewed the Balcoms on December 30, 2018, as the river was coming out of its banks for the fifth time last year.
Permitting Gauntlet and Post-Harvey Repairs
Rehak: You have a beautiful property here. Tell me the history.
Jim: Back in 2007, we started the permitting process through the city and FEMA. We went back and forth with them for two years. They were trying to shut down all building in the floodway and there was a huge lawsuit over it. But since we were in the process before they passed the ordinance about not building in the floodway, they let us finish. But dealing with them was very hard. I always tell people that if you want to buy property out here, you better look into it first.
It’s very soft sand down here. The engineer told us we would have to go 25 feet down to go 25 feet up with pylons. It’s flooding now at a rate that’s 10 times normal. (Pointing to the rising water) A few more feet and we have to pack our bags and get out of here!
The Encroaching River
Melissa: Before Harvey, there used to be a giant bank of trees just off our property that formed a little canal. You couldn’t even see the river. Harvey took all that out.
That peninsula went all the way down to River Grove Park.
Melissa: Now it’s all gone.
Jim: We decided we were going to move in here and we were committed. Our house is all steel framing. We have a hundred yards of concrete in the foundation. The first finished floor is 20 feet above the normal river level, but we still had one foot in the house, which is about where that window ledge is.
Rehak: Tell me about your prep before Harvey. You knew it was coming.
Melissa: We were ready to evacuate. We had our bags packed and were ready to go. We’d put everything up. At 3 a.m., we got a call from a friend in Conroe telling us about the dam release. So, we threw our bags in the truck and rushed over to another friend’s house in Trailwood. Our goal was just to get out. We thought the water would go under the house and everything would be fine.
That Sinking Feeling
Melissa: But before you knew it, our Trailwood friends were starting to flood.Their house had neverflooded. Then we’re in a panic trying to help them save their house…which is not on stilts. Then we heard that there was water in Kingwood high school and we knew that our house was flooded, because if water got in the high school, it’s high enough to flood us.
Jim: This neighborhood is slowly going away. Pretty soon, it won’t be here. There used to be a hundred homes here. Then it went down to 60 after the ’94 flood. Then 50. Now we’re down to 25. That house on the corner has water in it every time it floods. I don’t even know how they’re surviving.
Melissa: We moved here because my dad owned the lot for a long time. He’s a CPA by trade and does contracting as a hobby, too, so it was fun to think about building this kind of house. But it took six years to build. Everything took exponentially longer than it would to build a regular house.
Jim: We had to go 25 feet down before we got to any kind of stable ground. The engineer I used was from Galveston. There, they only go 10 feet down. Sometimes less.
He designed an 18-inch solid slab, with three layers of rebar and grade beams around the edge. It all ties into the pylons. We have 4×16 steel beams. It also has an 8-inch thick concrete stairwell in the center. Everything at ground level is designed to let the water flow through, like these louvered shutters.
Rehak: How did you determine the height of the first floor?
Jim: We built this house three feet higher than FEMA required.
Melissa: It was based on the ‘94 flood.
Jim: Downstairs, the slab is at 50 feet elevation. 56 is the height of the spillway at the dam. The water elevation is normally at 42.5. Our finished floor was 14 feet above the slab, or 64 feet. We thought we were smart to do that. But still, with all of that, we had a foot of water in the first finished floor. From the ground to where the water came was 15 feet.
So at this spot, the flood reached 65 feet.
Melissa: The neighbor’s house is set lower than ours. She had eight feet of water in hers. Hers was built 20 years before ours, so FEMA wasn’t requiring what they’re requiring now.
Rehak: So, they’re not permitting anything down here anymore?
Jim: After we got our permit, they tried to shut everything down. They let the people who had already applied continue. Then they tried to shut down all floodway permits, but later pulled back on that.
A Home’s Value
Melissa: You may have noticed the for-sale sign down the block. That lot has been for sale the entire time we have lived here. People come out here and they look at it and say, “Wow, look at this. This is really beautiful. It’s great. Then when they go to get the permit, it’s impossible to get because of the location.
Rehak: Is it impossible or just cost prohibitive?
Jim: It took us two years of steady work with the city. Then they said, OK, now you have to get FEMA’s approval. They did everything they could to talk us out of it. It was just one thing after another – endless stuff you had to do. And that was before Harvey when things were flowing better around here.
Rehak: So, having gone through all that, living in this gorgeous house with this gorgeous view, is it worth it in your opinion? Would you do it all over again?
Rehak: (Laughing) That was pretty quick.
Jim: It’s really scary to think you could lose your home.
Melissa: We will never be able to sell our house. It’s worth only what its value is to us. We can’t say, “OK, well let’s move.” There’s no way to get out of the house what we put into it. That’s because of Harvey.
Changes in River Behavior
Jim: We don’t know that for sure. I think anywhere on a waterway, you’re at risk. But what’s bad for us at this point is that it keeps flooding and keeps leaving mud in the yard and it didn’t used to do that. We’ve lived here for a long time. Every once in a while, water would come up in the yard, but nothing like it does now.
Rehak: In the eight years before Harvey that you lived here, how often did the water come up?
Melissa: Three times that we had to leave and go stay in a hotel. At 48 feet, the river starts to get in our yard. Anything over 50 feet, that’s when we have to leave to get our stuff out safely.
Endless Mud and Dead Trees
Rehak: What was involved in the cleanup?
Melissa: After Harvey there were two to three feet of sediment underneath our house. We had to get a bulldozer and push it all over the yard. Harvey destroyed a houseboat and another house just up the canal from us and left debris all over our yard. Then there were all the trees that fell. We had to pick those up, too.
Jim: We lost several 100-foot pine trees. They’re dying left and right from all the silt that the flood left on top of everything.
Melissa: That was the biggest part of the cleanup. The dirt everywhere. It gets in your house.
Rehak: How long did it take you to clean up after the flood?
Jim: We’re still cleaning. With this recent flooding, there are so many branches and so much mud, it’s hard to really get it cleaned up completely.
Eagles Outside Your Living Room
Rehak: You said there were eagles living around here. Tell me about that.
Jim: Lately, we’ve had them flying nearby. Two weeks ago, we had two full grown eagles fly into the tree behind the house. White headed. Full grown. We’ve seen them several times.
Rehak: Are you concerned about the impact of high rises on wildlife?
Soil Like Baby Powder in a Glass of Water
Jim: Yes, but a bigger concern is people’s safety. After spending two years to get a permit for this house, I can’t imagine how they would get a permit for all of that. The river is out of control. The flooding is out of control. And then to build a road! The soil is so unstable. It’s like if you poured baby powder in a glass of water. If you’re not from around here, you can’t imagine what it’s like. They would have to put in pylons. It would cost a billion dollars to do that. I can’t imagine how much money that would cost.
Rehak: Still, you chose to live here.
Jim: My son caught a 44-pound catfish right on that bank when he was ten. We have eagles perching outside our living room window.
Rehak: You are big nature people. If you take the anxiety of the flooding away, are you still happy you live here?
Melissa: Oh, absolutely.
Jim: We have the most unique house around. In some ways were the lucky ones. But we’re also the unlucky ones, too. In normal conditions, prior to Harvey, the water would get in the yard occasionally. But we never had to evacuate until the Tax-Day flood, the Memorial-Day flood, and Harvey. And those were followed by five more floods this year!
Future of North-Shore Area: Increasing Isolation
Rehak: What do you see as the future down here.
Jim: I feel like eventually were going to be one of the few remaining here.
Rehak: You’re becoming increasingly isolated. Is that good or bad?
Jim: We like the isolation, but I feel that we’re really at risk because of the river. We could lose everything we have.
Melissa: We budgeted for all the trouble. But we have friends in Trailwood and Kingwood Lakes that should have never flooded. That wasn’t supposed to happen to them. So, it was a lot more devastating to them…even though we live right here.
I thank the Balcoms and leave, thinking about the folly of permitting new structures in such a dangerous area, even as the County and City are buying out and tearing down hundreds of homes nearby that were destroyed by repeated flooding. With all the Balcoms did, they still flooded. And Romerica plans to build 5000 condos EIGHT feet LOWER than the level that the Balcoms flooded at.
Posted by Bob Rehak on 3/15/2019
563 Days after Hurricane Harvey
https://i0.wp.com/reduceflooding.com/wp-content/uploads/2019/03/HighWaterMark.jpg?fit=1500%2C915&ssl=19151500adminadmin2019-03-14 23:36:582019-03-15 09:40:33Jim & Melissa Balcom’s Hurricane Harvey Story: A Cautionary Tale