Cobbs Creek provides a unique feature to the golf course, but frequent flooding and channel degradation makes it a nuisance and eyesore. LandStudies, Inc. has proposed a design in which the floodplain and stream channel will be restored to maximize long-term stability and flood flow conveyance while providing a functional amenity as the centerpiece of the newly renovated course. 

The Past

Before we settled the area and altered the stream systems, the stream channel and floodplain were a connected system heavily vegetated with plant species native to the region and adapted to wet conditions. This vegetated network of plants helped slow excess flow and filter pollutants.  The soils in the wet floodplains allowed plentiful groundwater recharge, and the riparian plant life housed and nourished a wide variety of native wildlife. Wetland plants also absorbed nutrients such as phosphorus and nitrogen from the water and soils.

In the late 1600s, Europeans first began to colonize our East Coast, establishing farms and towns and industries along the landscape’s abundant rivers and streams. Streams were impacted by three important activities that took place concurrently over the years after settlement began – timber harvesting, farming, and mill dam construction.

Farmers and settlers quickly cleared land in the gentle slopes and bottoms of the stream valleys and often created straight channels along the edges of the valleys to redirect the water into a single stream, leaving the nutrient rich valley soils open for farming. Plowing these fields contributed to the soil erosion affecting the streams, and both animal and human waste contributed to excessive nutrients such as phosphorous and nitrogen. Phosphorus usually attached itself to the eroding sediment particles. Nitrogen more commonly found its way into the groundwater.

The new settlers from Europe were skilled in establishing mills and employing water power to drive them, and they did so rapidly. Throughout the region, one mill after another sprang up on nearly every river and stream. Mill races – long straight channels constructed to direct and control water flow over the mill wheel – diverted water from established channels. Flowing water behind the dams was slowed, becoming more like ponds than streams. It wasn’t long before the fine soils and sediments that were finding their way into stream valleys began to drop out in the ponded waters and build up behind the dams. As sediments built up in the ponded areas behind dams, both the channel bed and the floodplain rose. The channel bed, once gravel, now was sediment, also known as legacy sediment.

Mill and Dam Construction
Plan and profile views make it easy to see how water slowed and ponded behind dams and allowed sediments to build up behind the dams.

 

By the 1950s, several circumstances affecting our stream systems had changed. Wholesale land clearing had essentially ceased. Farm management had greatly improved. Human waste disposal was now largely controlled through municipal sewage waste systems. Water was no longer necessary for power. And industry was not forced to remain along streams. What all of these changes left in their wake was an elevated stream channel, an elevated floodplain, greatly diminished sediment loads coming into the stream valleys, abandoned mills, and crumbling dams.

Nature’s next step is what we are witnessing today.

Current Conditions/Before Restoration 

The Present – Cobbs Creek Floodplain Restoration

LandStudies’ approach to floodplain restoration speeds up the process of an unstable stream system working its way back toward stability, and it helps eliminate much of the damage that can occur to our now-occupied land and our infrastructure in the process.

The Cobbs Creek floodplain restoration design maximizes flood storage potential and creates a stable, natural floodplain that protects the primary golf features (greens, tees, fairways, etc.) and enhances the character and strategy of each hole. Approximately 12,000 linear feet of stream channel is proposed to be restored, and 25-40 acres of wetlands will be created resulting in a stable, ecologically enhanced ecosystem. The restored floodplain will be a significantly more stable system that supports a variety of plants and wildlife.  But the benefits go far beyond looking better, the proposed restoration will provide multiple regional benefits as well, including water quality improvement, flood storage, reduced erosion, reduced maintenance (especially bridge repairs), extensive functional wetlands that can be used as a banking opportunity and improved and enhanced wildlife habitat.

Historical or Restored Conditions

Examples of Floodplain Restoration on Golf Courses

Shobers Run at Bedford Springs Resort before restoration.

Shobers Run at Bedford Springs Resort after restoration.

Rock Run at TPC Potomac at Avenel Farm before restoration.

Rock Run at TPC Potomac at Avenel Farm after restoration.