Garner State Park Pavilion Preservation Study Location Map

9/12/2014
D4
Garner State Park
Pavilion Preservation Study
Presented by
Andy Johnston, PE, CPESC, CFM
Halff Associates, Inc. – Austin
Mark Winford, RA, LEED AP
Texas Parks and Wildlife Department, Austin
Location Map
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Civilian Conservation Corps (CCC)
Focus of Work
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Interrelated Items
CCC Pavilion Structures
FRIO RIVER
TERRACE
DANCE
FLOOR
CCC
PAVILION
HALL
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Pavilion Dance Floor
Pavilion Terrace
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Pavilion Drainage
FRIO
RIVER
Pavilion Drainage
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Pavilion Dance Floor: Bird Bath
Pavilion – Digital Scan
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Blue Shading Below a Given Elevation
Elevation = 1391.80
Digital Scan “Flooding”
Still Grades Toward River
1391.95
1392.05
1392.10
1392.15
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Pavilion Dance Floor: Settlement
Pavilion Dance Floor: Settlement
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Dance Floor – Edge Differences
Interrelated Items – Parking Lot
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Parking
Parking – Digital Scan
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Inlets/Pipes/Headwalls
Inlets/Pipes/Headwalls
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Inlets – pipes – wooden HW
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Erosion control on slopes.
Embrace historical methods.
“Planter boxes” for revegetation.
Key = get veg back on the slopes.
Green Gabion “planter boxes”
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View from the River
Vegetation Suites
Red mulberry
Desert willow
Burrowbrush
Lindheimer indigo
Lindheimer senna
Frogfruit
Knotgrass
Switchgrass
Common reed
Black willow
Arroyo willow
Water primrose
Smooth bidens
Bushy bluestem
Emory sedge
Buttonbush
Bald cypress
“Non-wet” plant types.
Equally “wet” or “non-wet” plant types.
Moderate “stability rating”
“Wet-footed” plant types.
Strong “stability rating”
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Permeable parking spaces
Porous pavement material
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Slope Erosion – cut through
Slope Erosion – behind wall
CCC wall footing exposed 
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Hindrances – foot traffic fencing
Include vegetative “fencing”
Hindrances – foot traffic fencing
Include vegetative “fencing”
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Hindrances – foot traffic (upstream)
Create a stairway?
Amenity? River access point?
Blend in with rock toe stabilization?
Controlled access point
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Interrelated Items - Streambank
Google Earth chronology (2012)
Meander pattern. Changing sides in our reach.
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Google Earth chronology (1995)
USGS Gauge – Uvalde
1997, June 22
2000, June 22
2002, July 2
2004, June 29
2007, July 21
100,000 cfs
100,000 cfs
189,000 cfs
72,300 cfs
74,100 cfs
Google Earth chronology (2005)
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Google Earth chronology (2008)
Google Earth chronology (2012)
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Stream has moved – opposite bank
CCC Original Plans
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CCC Original Plans
MAJOR GOAL:
Do not loose any
more streambank.
CCC Original Plans
MAJOR GOAL:
Analyze the bank
and wall for
structural stability.
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FEMA Floodplain
Zone A
1967 Channel Improvements
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1967 Channel Impingement
2005 Channel Work
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Stream – rock blocks (2005)
downstream
upstream
Stream – rock blocks
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Stream – rock blocks
Stream – rock blocks (footing)
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Stream – rock blocks (upstream)
Stream – steep bank
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Riparian Zone – values and functions
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Values (the things we want)
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Recreational value.
Aesthetic beauty.
Wildlife habitat. Forage.
Aquatic habitat.
Water quality. Water quantity.
Functions (the things we can influence)
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Dissipate stream energy.
Trap sediment.
Stabilize banks.
Reduce erosion.
Store water. Sustain baseflow.
Groundwater recharge.
Creek Doctors
 What is the least amount of work that needs to be done to make
things better?
 What things are still working fine?
 What is throwing the system out of balance?
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 Each “patient” is different. Listen to unique needs.
 Holistic approach (park use, environmental, stabilization).
 Use “natural channel design” concepts. Recruit vegetation.
Sustainable design.
 Potomology. The systematic study of the factors affecting river
channels to provide the basis for predictions of the effects of
proposed engineering works on channel characteristics.
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Alternatives
 Resist
Usually continuous, applied directly on the bank, or
toe, or both, offers resistance to river or stream forces,
some methods can self-adjust, others are rigid.
 Redirect
Indirect, usually discontinuous techniques that redirect
flow & energy of the river or stream away from the
area of the eroding bank.
Resistive (continuous)
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Natural features (rock outcroppings, blue clay, etc.)
Loose Rock Riprap (filter stone layer, “soil choked” surface)
Boulder Blankets (bank paving)
Grouted Riprap
Root Wads
Log Revetment
Trenchfill (setback revetment)
Sack Revetments (RRap)
Windrow Revetment
Soil Cement
Gabions
Sheet pile
Concrete
Retaining walls (to include cellular confinement layers)
LUNKERS
Longitudinal Peaked Stone Toe Protection (LPSTP)
Longitudinal Fill Stone Toe Protection (LFSTP)
Self adjusting (sustainable). Foundation is critical.
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Redirective (discontinuous)
 Impermeable Dikes, also called Spurs, Groins, Jetties
including Stone-Filled Pile Dikes and Stone-Filled Dikes.
 Permeable Dikes (Pile Dikes, Palisades).
 Vane Dikes.
 Contraction Dikes, or Wingdams.
 "L" and "T" Head Dikes.
 Upstream & Downstream Angled Deflectors (Bank Barbs, Rock
Vanes, Rock Vanes with J-Hooks).
 Bendway Weirs (many variations including L& T-Head
Bendways).
 Engineered Log Jams.
 Kellner Jacks, Tripod Jacks, Tetrahedron Jacks
 Hard Points (also called transverse dikes, always normal to the
flow.
 Kickers and Missouri River Kickers.
 Deflectors (also "wiggle" deflectors) and false point bars
Stream – scour pockets
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Stream – scour pockets
Stream – scour pockets
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Stream – scour pockets
Enhance opportunities to trap sediment, recruit vegetation,
dissipate energy, create a naturally armored toe,
and help stabilize the upper slope (less steep).
Large rock boulders (stable reach)
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Armor toe + Harvest sediments
Stream – create sediment traps
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Stream – deposition - colonizers
Stream – stabilizers – root wads
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Stream – remove/relocate point bar
Slope and toe protection (plan view)
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Riparian Zone – values and functions

Values (the things we want)






Recreational value.
Aesthetic beauty.
Wildlife habitat. Forage.
Aquatic habitat.
Water quality. Water quantity.
Functions (the things we can influence)






Dissipate stream energy.
Trap sediment.
Stabilize banks.
Reduce erosion.
Store water. Sustain baseflow.
Groundwater recharge.
Interrelated Items
36
9/12/2014
D4
Garner State Park
Pavilion Preservation Study
Presented by
Andy Johnston, PE, CPESC, CFM
Halff Associates, Inc. – Austin
Mark Winford, RA, LEED AP
Texas Parks and Wildlife Department, Austin
37