Retention/detention Ponds

[dbat_01]

I have a friend who is an architect here in town that absolutely loves retention ponds because of having water features on site, I on the other hand think they are a waste of real estate, they breed large crops of mosquitoes every year, and if they are not turned into an actual pond and properly taken care of they become an eye sore. I am looking into going into a business that would eliminate the retention pond and place it underground beneath parking lots (commercial use) and driveways (residential use). This system will also retain rain water, and with the use of a simple pump you can use that rain water for irrigation rather than using potable water. It will also add 12 LEED points to any green building that is to be built. My question to you is: Are retention ponds an eye sore and do you feel that we need a solution to get rid of them?

[RedScare]

Yes and No. The one's that are designed well, like your friend describes, can look decent, but there are many that are ugly holes in the ground, like you describe. The rentention pond at Lowe's on the North Loop comes to mind.

Clearly, your idea would be very useful to a developer with a limited amount of space. And I love water the grass with rainfall runoff as opposed to using city water.

Any idea as to cost benefit, or is that a trade secret?

[Original Timmy Chan's]

First of all, ponds CAN be designed to be very nice, but it does take more planning, more land, and more maintenance $$$. I think the pond at Art Storey Park on the West Belt is a very good example.

Of course, without maintenance, these ponds can turn into a major liability for the owner. So it's pay me now or pay me later for the owner (on-going maintenance costs vs. lawsuit).

10 years ago, most detention ponds were an ugly hole in the ground hidden as far from view as possible. Today, most developers are trying to incorporates their detention ponds as amenities, whether they have a permanent pool, or walking trails, picnic areas, playgrounds, etc. So today, the ponds are less a "waste of land" and more of a beneficial use of land.

As for your business plan, it's an interesting concept, but you need to look at how practical it is. I have heard that there is only one place in Houston that's used underground detention storage, and that's a post office in the Galleria area. For large developments, the price of land is cheap enough, and the amount of volume required is so large that it's not practical to use underground detention storage.

Therefore your business will be dependent on site development, not large-scale land development.

Look at the costs of building your detention vs. traditional detention: you still have to provide the same storage volume (actually, using a pump, you probably need more storage than a traditional gravity system, but let's simplify). So, you need to excavate the same amount of dirt out of the ground. However, in your system, you also need to provide a pump station (including controls), and most importantly you'll need to provide lots and lots and lots of underground pipe to provide your storage. And pipe's not cheap. Now, if you're going to hold all that water for irrigation, you'll need to provide two or three (or more?) times as much volume, in order to have storage available to hold that next 100-yr rain event.

Now you've added a LOT more detention cost for pumps, controls, additional storage, and thousands of linear feet of pipe. Does all that extra cost outweigh the cost of losing approximately 12-15% of your land for traditional detention? Well, as I said, there's only one development in town that's used underground detention storage (or so I've been told). One development out of thousands and thousands.

Good idea, but it will probably have limited potential due to the low costs of land in Houston.

[wharton transplant]

I think the city ordinances that have gone into effect in only the past 4-5 years are starting to have a positive impact on landscaping. With these anti-blight measures forcing developers to invest in trees, shrubs, and other landscaping assets for commercial properties (such as around parking lots), it seems that retention ponds would also be affected. Therefore, "pretty" holes in the ground would be required to be built (and maintained?).

I don't know what the ordinances are, exactly. But it took years for the city to get them enacted and enforced, apparently.

[dbat_01]

The thing about this new concept, is that it is modular and there is no pipe(other than the pipe used for irigation). This product is called a rain tank and it is made out of post consumer recycled material. It basicaly looks like a milk crate that is stacked as high and as long as needed to meet the EPA regulations on foot acres of water required per acre of dirt moved, and is wrapped in a mesh cloth that acts as a filter that cleans sediment out of the water. There are two pipes conected to this system, one for overflow that pushes clean water into our streams and bayous and the other for irrigation. Commerica Bank is in the process of adding these raintanks to their new facility. As far as pricing is concerned, it would cost the same to buy the realestate and dig the hole as it would to buy these systems. The difference is the wasted opportunity costs you lose with retention ponds. The other interesting use for this product is ditches. You can put these in any ditch, cover them with soil and grass and they will retain water until the land absobs it or it flows into the streams and bayous. Again it eleminates mosquitos and prevent people from running into colverts and ditches with their cars.

[Original Timmy Chan's]

The thing about this new concept, is that it is modular and there is no pipe(other than the pipe used for irigation). This product is called a rain tank and it is made out of post consumer recycled material. It basicaly looks like a milk crate that is stacked as high and as long as needed to meet the EPA regulations on foot acres of water required per acre of dirt moved, and is wrapped in a mesh cloth that acts as a filter that cleans sediment out of the water. There are two pipes conected to this system, one for overflow that pushes clean water into our streams and bayous and the other for irrigation. Commerica Bank is in the process of adding these raintanks to their new facility. As far as pricing is concerned, it would cost the same to buy the realestate and dig the hole as it would to buy these systems. The difference is the wasted opportunity costs you lose with retention ponds. The other interesting use for this product is ditches. You can put these in any ditch, cover them with soil and grass and they will retain water until the land absobs it or it flows into the streams and bayous. Again it eleminates mosquitos and prevent people from running into colverts and ditches with their cars.

Interesting. Do I understand you correctly, that these "rain tanks" aren't water tight? They would allow some water to percolate into the ground?

Previous underground storage systems that I've heard of are either corrugated metal pipe, corrugated HDPE pipe, or reinforced concrete pipe...all of which have been prohibitively expensive.

[dbat_01]

This product is made out of recycled polypropylene, making it lightweight and modular. the traditional underground retention pond is made of steel or concrete pipe and is expensive, as you said. The other great thing about this product is that when you dig the hole to place the underground detention pond, the product will fill 95% of the hole leaving 5% extra to wrap the geotextile cloth around the tank, whereas other products require 70%, with 30% excess. Below is the website if anyone is interested. www.atlantiscorp.com.au. The cost would be appr. $5 per sq.ft.