An exercise in stream restoration and redesign Tanyard Branch An exercise in stream restoration and redesign Given by: Sarah Hibbs September 29, 2003 -Degraded urban streams are a growing problem across the nation. -watershed and riparian deforestation, road crossings, pipes and culverts, toxic pollutants, and impervious surfaces all contribute to the threats that face our urban streams.

What is Tanyard Branch? An Urban Stream which runs through The University of Georgia campus, beneath Sanford Stadium 50% of Tanyard Branch is piped Channel banks and streambed are highly eroded Water does not meet water quality regulations Poor habitat for insects and aquatic life Stream is cut off from human interaction Tanyard branch is a stream that runs through the University of Georgia campus and beneath Sanford stadium -tanyard branch illustrates many of the problems that plague urban streams

The University of Georgia Current UGA campus map

Tanyard Branch Now Notice: highly eroded stream banks, the lack of substrate in the streambed, not very sinuous, trash is covering everything, riparian zones are invaded by human affects

Sedimentation, point source pollution, erosion, pipes running overhead

More point sources for pollution, storm drains with gigantic cement slabs trying to shore up the streambanks, highly eroded banks

More sources for point source pollution, stream channel side is completely cemented up---no riparian zone at all, undercutting

Streambank ersosion

Pipes and culverts, stream banks completely impounded, severe undercutting, no riparian zone, no ability to infiltrate and have groundwater feed stream (impounded)

Terraced and cement constructed bed, completely dry streambed

History of Tanyard Branch Tanyard branch changes from a sinuous, unrestrained stream channel to a straightened, culverted, and highly degraded urban stream. --even as early as 1874, the area surrounding the stream is highly urbanized, but the riparian corridor has been maintained and the stream has been allowed to flow unrestrained and inhibited. 1874 Map of Athens, Georgia (Tanyard Branch highlighted in blue)

1909 birds-eye view of Athens, Georgia In 1893, a city reservoir on tanyard’s south branch was added, where legion pool is today. This picture shows the reservoir and a meandering stream channel. Map shows that tanyard still maintains a natural sinuous path of waterflow. --somewhere between 1909 and 1924, photos show that the stream channel was relocated from its position to the edge of the valley to make room for the old UGA baseball field. By 1959, the ressivoir is gone and drainage maps show several first order tributaries that fed Tanyard branch (all of these tributaries are piped now) 1909 birds-eye view of Athens, Georgia

1993 aerial photo of Athens, Georgia 1993 aerial view shows a highly urbanized watershed. --research has shown us that the channel of the current tanyard creek is not in the original channel, but pushed to the edge of the valley against steep bluffs on the south bank to make more room for campus activities. The historical channel bed is through the tate center parking lot’s current location. 1993 aerial photo of Athens, Georgia and the University of Georgia campus

Major Concerns Stormwater Vegetation and aquatic habitat Problems—for urban streams and for Tanyard Branch Strategies for repair and management Vegetation and aquatic habitat Geomorphic reference conditions, watershed and hydrologic assessment

Stormwater concerns in an urban setting Channel instability—eroded banks and stream beds Increased peak storm flows Reduced baseflows Water quality impairment (including increased temperatures, toxic pollutants, nutrients, turbidity and sediment Habitat degradation Biological impairment

Stormwater and Tanyard Branch Lumpkin Tanyard culvert November 10th Lumpkin Tanyard culvert Culvert filled to capacity, September 14th

Stormwater and Tanyard Branch Sanford Tanyard culvert Culvert filled to capacity, September 14th Sanford Tanyard culvert November 10th

How to deal with Stormwater Traditional Methods Conveyance—storm drains, street gutters, culverts—anything to channelize to the nearest stream Detention—wet and dry detention ponds, stormwater wetlands Desirable Methods Infiltration—shifts balance of water from surface water back to groundwater—uses things like rain gardens, porous pavers and green roofs.

Alternative stormwater strategy 1 Cisterns that collect stormwater from rooftops and condensate from air conditioners Retrofit sidewalks with porous paving Include green roof design on roof upgrades of existing buildings

Alternative stormwater strategy 2 Vegetated infiltration basins (rain gardens) with terraced inflow dissipation Water from parking lots is collected conventionally, but not shunted into a new storm sewer system.

Water from parking lot is filtered through several stilling wells, and filtered through an Alluvial fan, which slows fast moving water and allows for sediment deposit. From the alluvial fan, water is infiltrated in a series of rain gardens

Alternative stormwater strategy 3 Floodplain rehabilitation—replace impervious surfaces in the floodplain with riparian wetlands The floodplain is an integral part of biological habitat, as well as stormwater management

NC State’s campus stream, Rocky Branch, once had steep banks, but the floodplain has been reestablished and will soon be reforested.

Vegetation Suggestions List of typical plant communities for the riparian zone and uplands Drawn from other stream corridors in the Georgia piedmont

Aquatic Habitat Clean, large sediment, consisting of pebble and cobble, for spawning and feeding Bedrock for feeding and cover Pools, especially deep pools, to provide refuge during drought or low flows Riffles, for feeding and spawning, especially important for small-bodied fishes Woody debris for feeding and cover

Geomorphic reference conditions, watershed, and hydrologic assessment Tanyard channel is currently south of historic location—redesign incorporates the relocation back to its previous channel Channelization (straightening) is another major problem for Tanyard branch—redesign will use a reference stream in the North Carolina piedmont (data includes: sinuosity, width:depth ratio, and meander belt width:width ratio) to replace the natural curves and meanders previously lost

Watershed assessment was conducted to assess appropriate channel size Watershed assessment was conducted to assess appropriate channel size. Using a DOQQ for Clark County, watershed parameters were calculated using the ERDAS Imagine GIS software. Table 1: GIS analysis results for Tanyard branch watershed Watershed Parameter GIS Analysis Results Watershed area in square miles 0.782 Watershed % (forested) 20.7 Watershed % (impervious) 73.8 Watershed % (shadow—photo error) 5.4

Tanyard Branch Redesign of Campus Using the campus master plan, several conceptual designs were submitted with Tanyard Branch as the focus. Changes include: Elevated road extensions, new buildings and dorms, community outreach centers and other important features to the functioning of the center of UGA’s campus

University of Georgia Master Plan

Design Proposal A Conceptual Plan

Design Proposal A Detailed Plan

Design Proposal A Detailed Images

Design Proposal A Detailed Images

Design Proposal B Conceptual Plan

Design Proposal B Detailed Plan

Design Proposal B Detailed Images

Design Proposal B Detailed Images

Design Proposal B Detailed Images

The Ultimate Goal

GO TECH!