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Mudboils
AEES Pre-Conference WorkshopWednesday, June 6, 2012
Nate BarletBrandon Winfrey
Roy Wood
Problem Statement
• Turbidity in Onondaga Creek too high to support species historically present• Sediment load to the creek
from mudboils has been identified as major contributor to turbidity
Goals and Objectives
• Improve Onondanga Creek to support fish species present upstream of the mudboils– Intercept 100% of sediment load from mudboils. • This will protect river ecosystem from ever being
affected by mudboil sediments that increase turbidity
Design Constraints
• Landowner– Honeywell
• Hydrogeology– Unclear
• Environmental• Energy• Cost– Dredging may
be required
Potential Solutions (1)
• One Large Relief Well– Attempt to create mudboil in the existing area to
control source of sediment• “One Well to Rule them All”
• Advantages:• Control source• Easier to design sediment
abatement
• Disadvantages:
• Unclear if control is possible• Low flexibility if other
mudboils appear
Potential Solutions (2)
• Divert Creek around mudboils, Contain mudboils– Build impoundment around entire area– Move creek channel into field adjacent
• Advantages:• Creek avoids sediment loading
(never impacted)• Mudboils potentially capped by
hydraulic head
• Disadvantages:• Expensive
• May create mudboils down gradient
• Creek channel may migrate back to mudboil area
Potential Solutions (3)
• Impoundment around rogue mudboil, Wetland for smaller particle removal, relief wells– Build impoundment around rogue mudboil followed by
wetland– Surround impoundment by relief wells– Construct levee to protect creek
• Advantages:• Protects creek from incoming
sediment• Provides ecological and aesthetic
service• Flexible design
• Disadvantages:
• Storm events could decrease sediment capacity
• Annual dredging required• Large land area required
Design Overview
• Relief Wells assumed to control flow from mudboils to not exceed 400 gpm
• Impoundment designed to contain particles > 4 μm
• Wetland designed to remove smaller particles (< 2 μm)
• Levee high enough to protect creek from storm events
Relief Well Design
• Install 4 relief wells surrounding impoundment berm – 5” diameter with screens excluding sand
size particles– Installing 1 well next to mudboil can
potentially reduce hydraulic head by 15 ft.
– Install wells 20 ft. from mudboil vent to prevent intercepting sediment flow in vent
Impoundment Design (1)
• Dredging is unavoidable– Annual dredging– Design to remove 4
μm particles • Settling velocity of 6
x 10-4 cm/s• 38 hr detention• design driven by
solids dredging annually, not settling time requirements
Impoundment Design (2)
• 35 meter diameter• 6 ft high• 3 feet water level design• walls are 3 foot wide top, 3:1 slope, 13 ft
bottom
Profile View: Impoundment
Mudboil cone
Drains to Wetlands
Wetland Design (1)
• Sheet flow over vegetation to remove particles smaller than 2 μm.
• 155 acres• size driven by solids limit to 2 cm/yr depth• <1 acre needed for solids removal retention
time
Profile View: Wetland
4 % slope
Design Overview
Estimated Cost
• $45,000 based on $15/cu. yd.– Includes berms for access to impoundment and
levee• $5 million for bio-swale– Based on estimated cost per acre of $35,000
Other Considerations• Problem of source too large to contain• Salinity diluted in stream to lower levels
– Salinity in relief wells presumed to decrease (drawing from freshwater aquifer)
– Not included in treatment goal• Snowfall my decrease residence time in winter• Do relief wells control flow from mudboils to below historic high flows?
– Studies on effects of relief wells on mudboil flow should be done• Pilot-scale study on effectiveness of wetland
– Vegetation response to sediment over time– Fine particle removal rates
• Construction should occur in phases– Install relief wells first, allow some time for mudboils to react (1-2 years)– Build levees and impoundment around stabilized mudboils (1-2 years)– Construct wetland, route water from impoundment through wetland (20-
year design life)
Summary
• As designed, sediment load from mudboils intercepted before entering Odondanga Creek– Ecological buffer (wetland) between mudboils and
creek should enhance recovery of fish populations – Levee would prevent resuspension and
conveyance of sediment to creek during storm events
– While dredging required, sediment has astringent qualities that could have market value as a cosmetic product
Questions?