Tanyard Branch
An exercise in stream restoration
and redesign
Given by: Sarah Hibbs
September 29, 2003
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
The University of Georgia
Tanyard
Branch
Now
History of Tanyard Branch
1874 Map of Athens, Georgia
(Tanyard Branch highlighted in blue)
1909 birds-eye view of Athens, Georgia
1993 aerial photo of Athens, Georgia
and the University of Georgia campus
Major Concerns
• Stormwater
–
–
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
Lumpkin Tanyard culvert
November 10th
Culvert filled to capacity,
September 14th
Stormwater and Tanyard Branch
Sanford Tanyard culvert
Sanford Tanyard culvert
November 10th
Culvert filled to capacity,
September 14th
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.
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!