Quote:
Originally Posted by Jdawgboy
The problem with any road is it's imperious cover and that of course means any rain water that falls on it will wash away. The water collects along the stretch of road, builds up volume and speed. It also picks up other fluids such as oil along the way.
It's easy to see the effects of what covering large amounts of land does to area creeks. At one time creeks like Shoal, Bouldin, Williamson, Waller, Onion, Slaughter ect... (mostly named creeks south of the river because those are the ones I know best but you can add to the list), had water in them throughout the year except during prolonged droughts. As the city grew around them, water runoff became more intense and damaging stripping the natural riparian plantlife which was important in slowing the water down. today most of these creeks lay dry. Even after recent rains, they are quick to drain out. We know so much more now than we did 50 to 100 years ago and there are ways to repair some of the damage by replanting native riparian species. Other measures include catching fast running water from drains and sewers into rain gardens.
This is going to be a fundamental struggle for a long time. To find the balance between human need and environmental need will take understanding and effort.
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That is all true, however, thanks to the Save our Springs ordinance any new project built in the aquifer recharge zone must have no more than 35% impervious cover and is required to have 100% runoff recapture.* For buildings, highways, parking, etc. this means you have to direct the water to what's called a containment pond or detention pond. "Pond" isn't the best descriptor since most of these never actually hold water, they filter it. You see them all over. Skateboarders love them. They are those concrete-walled, sunken areas that are next to parking lots, major highways, apartments and office buildings that usually have grass growing in the bottom. Underneath that grass is a filtration system that includes gravel, sand, mesh and other miscellaney, and the filtered water is then directed to the sewer.
These ponds don't filter the runoff into 100% clean water, of course, but they mitigate the pollutants. In other words, you don't poison the land and water as
quickly as you would without runoff recapture. In other parts of town your required runoff recapture is much lower. Sometimes as low as 25%. To get to 100% recapture and 35% impervious cover, you have to have a lot of extra land to set aside as greenbelt just to build your project. It's why you don't see many massive surface parking lots over the recharge zone, except for Barton Creek Mall, which when built was what spurred SOS to be created to fight for the Save our Springs law in the first place.
There is a part of the SOS ordinance that says any project that had a valid development permit in place before the bill passed is 'grandfathered' and can be built under the same conditions as originally approved. That's how many of these projects are getting around the aquifer protections. The land owners and developers just keep renewing their development permits until they get the funds together to build the project, or find a buyer willing to do it.
*And before anyone brings it up...it is not physically possible to have 100% runoff recapture in the real world, but the law has a set of criteria that defines 100% recapture and as long as a developer can prove to the city that they meet the criteria their permit will be approved.
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