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A Novel Approach to Flood Management Saves City Millions

by Jim Wahl, President of Wahl Marketing Communications, and Shawn Hara, City of Longview, Texas

Thinning of forested areas near Grace Creek mitigated the flooding while preserving the natural beauty of the area and saving over $17 million.

A novel approach to flood management saved the city of Longview, Texas millions of dollars while preserving the natural beauty of the area. Nearly 6 miles of Grace Creek flows through downtown Longview before it empties into the Sabine River.  Much of the land along the river is nearly flat and is prone to frequent flooding.  A heavy overgrowth of brush inhibited the flow of floodwaters and raised upstream water levels. To reduce flooding, the Grace Creek Floodplain Management Project sought to reduce the 100-year flood levels of Grace Creek by as much as 2.2 feet.

Two options were initially considered. The first was a structural option that would require the construction of a drainage channel from 55 to 75 feet wide to rapidly remove floodwaters from the area. While effective, this option would have dramatically (and adversely) impacted the natural setting of the Grace Creek area and the wildlife therein. This coupled with a hefty price tag of more than $20 million prompted the city to seek an alternative.

A second option called for removing the existing underbrush and allowing the remaining hardwoods to develop into a mature forested floodplain with complete tree canopy coverage. This option was selected because it still mitigates the floodwater damage, yet does so without compromising the natural beauty of the area.

A Two-Phased Approach
Work proceeded in two phases – with work along the southern portion (Lower Grace Creek) accomplished first, followed by the northern portion (Upper Grace Creek).  Initially, areas within both Upper and Lower Grace Creek that were to be managed were identified utilizing three techniques:

  • Removing approximately 50% of the woody vegetation by mulching a 16 foot wide row and leaving a 16 foot wide row un-mulched
  • Selectively removing some of the merchantable hardwoods less than 20 inches in diameter while saving any tree larger than 20 inches in diameter. Effort was made to leave a timber stand with enough trees that, as they grew, would develop into a mature hardwood forest. After removing the merchantable hardwoods, “mulching” the brush, unmerchantable hardwoods and logging debris, and finally
  • Clearing some areas prior to planting of loblolly pine and various native hardwood species. Where areas were open (pasture/grass) or were overgrown with brush and/or weeds they planted with either loblolly pine or hardwood tree seedlings.

Throughout the project, emergent wetlands, creeks and intermittent drainage areas remained undisturbed.

Phase 1 focused on Lower Grace Creek. Terry Anderson and J. Mike Bird of Advanced Ecology Inc., an environmental and natural resources consulting firm in Center, Texas were selected as the local contractors. Bird recalls that the project “had a tremendous amount of brush and hardwood (undergrowth). We were able to remove the vegetation without being intrusive and without a lot of soil disturbance.”

Phase 2 focused on Upper Grace Creek. While similar in the scope of work to be done, there were no areas to be cleared and reforested.

The Right Equipment Was Essential
Bird recalls using two different pieces of equipment on the project – which spanned nearly 3 years. The first was a Tigercat 760M, a 425-horsepower 4-wheel drive carrier with a Fecon Bull Hog mulching attachment mounted on it. This combination was ideal for the clearing of large areas – like the 16-foot rows and the clearing prior to re-forestation in other areas.

The selective thinning was a bit trickier.  Bird said, “We saw that there was a need for a smaller machine - so we ordered a Franklin 3650; it’s a 3-wheeled piece of equipment.” This 200-horsepower machine features a slightly smaller mulcher. Its enhanced maneuverability was ideal for getting around the reserved trees, while removing the undesirable trees and underbrush.

With any equipment, durability and service life are the keys to productivity – in harsh working conditions like the Grace Creek Floodplain Project – they are even more critical.

Bird said “We had an opportunity to lease a couple of 450 horsepower machines with flail type heads on them. They were a maintenance nightmare.”

“At the end of an 8-week period,” Bird continues, “we looked back on the production – the amount of time that we were actually running the flail hammers versus the Fecon. On a per-machine basis the Tigercat and Fecon combination were four times more productive than a swinging flail machine. (You) can’t attribute all of that to the head because there were some other mechanical problems, but a considerable amount of it can be directly related to how well the head services.”

Selective thinning of wooded areas allowed waste trees and underbrush to be mulched efficiently and economically while saving selected trees.

Dramatic Results
The project saved the taxpayers an estimated $18.2 million (as compared to the structural method of flood management).  In addition to the benefits the project provided in terms of flood prevention, a great benefit was achieved for the citizens of Longview due to enhanced aesthetics of the area. Environmental assessments completed along Grace Creek have identified over twenty varieties of native trees and a number of shrubs, vines, and grasses. Nature enthusiasts are able to view the flora in a variety of growth stages. Wildlife is abundant and visible signs indicate the significant presence of deer, birds, and reptiles.

The project allowed for the preservation of this natural setting and afforded many opportunities for recreation and natural resource education. One such opportunity the establishment of Paul G. Boorman Pedestrian and Bicycle Trail, scheduled for completion in February 2006. The park will benefit Longview area citizens by becoming a transportation alternative for bicycle and pedestrian traffic that normally travel on nearby roadways. In addition, a scenic, improved pathway system will provide access to those who enjoy observing and studying nature. It is also anticipated that the addition of new trails in Longview will expand the opportunities for physical activity. By offering this unique opportunity for nature study, it is hoped increased tourism will result in economic benefits to the area.

Time or money costs:

Purchase of 810 acres of Floodplain property = $1.5 million
Total Engineering Costs: $233,700

Phase 1: Southern Section (FM 1845 to US Hwy 80)
Clear and Replant 158 Acres = $220,000
Enhance 216 Acres = $190,000
Total Estimated Initial Cost = $410,000
Cost of Maintenance: $35,000 phased to $15,000 over 5 year period = approx. $125,000

Phase 2: Northern Section ( US Hwy 80 to Loop 281)
Total Estimated Initial Cost = $200,000
Estimated Cost Including Maintenance = $340,000

Total Estimated Cost of Project excluding Maintenance = $2.5 million vs. $20 million (estimated for Option 1)

A community working together
The level of community cooperation on this project was very high. The Engineering firm responsible for the planning and consulting is based in Longview and the contractor – Advanced Ecology is based in neighboring Center; so each was firmly committed to success of the project. In addition, the replanting of pine and hardwood trees was handled largely by a local volunteer group – the Hardwood Association. The Paul G. Boorman Pedestrian and Bicycle Trail is another example of community involvement. This trail may not have been possible without the support from individuals and organization that wrote letters to the Commissioners of the Texas Department of TransportationSelection of the option that preserved much of the natural beauty and wildlife habitat while providing increased flood protection produced a win-win solution.

For more information contact Fecon at www.fecon.com, info@fecon.com, (800)528-3113 or contact Advanced Ecology at www.advancedecologyinc.com, info@advancedecologyinc.com or contact Wahl Marketing at www.wahlmarketing.com, jim@wahlmarketing.com.