Watershed plan attempts to deal with growth's impact

By Guy Busby
Government Editor
Posted 6/10/22

DAPHNE — Growth and development are affecting local watersheds dumping many times the normal amount of sediment into local streams, environmental experts said.At a stakeholders' meeting of …

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Watershed plan attempts to deal with growth's impact


DAPHNE — Growth and development are affecting local watersheds dumping many times the normal amount of sediment into local streams, environmental experts said.

At a stakeholders' meeting of Baldwin County residents and officials organized by the Mobile Bay National Estuary Program, participants said waterways throughout the Eastern Shore are being affected as more land is developed.

"In Fly Creek we've got a pretty good boost in population," Suzanne Sweetser of Thompson Engineering said. "Pretty much throughout the watershed study area, there's going to be a significant increase in population, except for when you get into the southern sub-watershed and that's because these areas have a lot of wetlands and so they're naturally more difficult to develop."

Sweetser said more development means more land covered in roofs, concrete and asphalt and other surfaces that will not allow water to soak into the ground.

"Increased urban development leads to the highest sediment loads and the reason why that happens is as you have increased development, every structure is an impervious surface," Sweetser said. "We're not just talking about concrete. We're also talking about roofs."

More water running off impervious surfaces increases the volume of water carrying dirt and sediment into local streams. The average amount of sediment expected to be carried by a creek is about 64 tons a year, she said.

Studies conducted for the Mobile Bay NEP found that Red Gully on the Eastern Shore was carrying more than 15,000 tons of sediment a year. Tatumville Gully was carrying 5,581 tons, Rock Creek was carrying 4,644 tons and a Fly Creek tributary was carrying 1,636 tons, Sweetser said.

"Red Gully, Tatumville Gully and Rock Creek were the highest sediment loads in both Mobile and Baldwin counties, so those gullies need to be focused on," she said.

Sweetser said different watershed areas require different techniques to control erosion and sedimentation.

"In some areas, pervious pavements and other materials built to allow water to percolate into the ground have not been maintained. If pervious pavements are not cleaned, such as being pressure washed, the cover can become clogged with dirt," Sweetser said.

"If you aren't cleaning out those pervious pavements, then eventually, they become compacted and act just like impervious pavements," she said.

In some areas, living shorelines, protected stabilized areas made of natural materials such as plants and sand instead of bulkheads, can help reduce waterfront erosion. Sweetser said education programs can help some property owners understand the benefits of living shorelines.

"One of the things that we talked about was folks who are uncertain about doing a living shoreline and they don't think that it's going to work," Sweetser said. "They've never seen one in real life. So, if we can take them to places, locations where they've been installed and they've held up, we think that's going to make people a lot more likely to want to accept them."

Litter and debris were another issue discussed as part of watershed maintenance. Sweetser said litter is not as much of an issue in Baldwin County as it is in Mobile.

Richard Johnson, Fairhope public works director, said local agencies attempting to clean streams sometimes have difficulty getting help from agencies such as the Federal Emergency Management Agency.

"One of the challenges I think we all faced from different municipalities or government jurisdictions after (Hurricane) Sally, we may have had in our FEMA contract waterway cleanup, but the problem is FEMA came back and said, 'we will not reimburse you on that because that's another federal agency's responsibility.' And you'd go to that federal agency, and they'd say 'we're not going to do it. We don't have the money.' So, if you want it cleaned, you go clean it and you eat the cost. There's got to be some ability that these streams and creeks within our jurisdictions that we can get that storm debris out and be made whole, being good stewards of that, instead of playing the 'hot potato' game between federal agencies that are supposed to be doing it, but don't take responsibility for it," Johnson said.