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The purpose of this project was to evaluate the Talking Water Gardens
wetlands designed by CH2MHILL in Albany Oregon and determine if a similar
constructed wetlands system would be feasible for treatment plants in Bend Oregon.
Talking Water Gardens accepts effluent from two wastewater treatment plants and was
commissioned with the primary goal of mitigating high temperatures in treated
wastewater effluent prior to discharge into the Willamette River. High temperature
effluent into the Willamette River is harmful to local temperature-sensitive fish (e.g.
Salmon and Steelhead). The hydrology of Talking Water Garden was studied and used to
create a simplified simulation of temperature mitigation. This simulation was then
applied to the proposed site in Bend Oregon.
Phil Caruso, Stephen Clarke, Travis A. Grohman,
Liz Jachens, Leslie Jensen, Suvadee Thankitkul
30 November 2015
Constructed Wetlands For Wastewater Treatment:
Evaluation of Talking Water Gardens in Albany Oregon and Feasibility of a Similar System in Bend Oregon
Wetland Basics- What is a Wetland?
Areas where the water table is at or near the surface
of the soil all year or for varying periods of time
during the year (US. EPA).
Characterized by hydrophytic vegetation and hydric
soils
- Wetland HydrologyP+Qin+GWin=ET+Qout+GWout+ΔS
- geology, climate, topography determine:
distribution, type, vegetation and soil
Components of the wetland water budget(Source: USGS)
Talking Waters Water Balance Evaluation Other Locations ConclusionWetland Basics
Wetlands effect on water quality- Can maintain or improve the quality of entering
water.
- Wetlands have the ability to filter out natural and
anthropogenic materials like:
- Sediments
- Nutrients
- Heavy metals (Pb, Cu, Fe and Zn)
- Temperature (if conditions allow)
- Filtration ability is dependant upon
- soil
- vegetation
- water flow (residence time)
- microbial populations
Talking Waters Water Balance Evaluation Other Locations ConclusionWetland Basics
Constructed vs Natural Wetlands- What is a constructed Wetland?
- An engineered, man-made system that mimics the natural processes associated
with wetland soils, vegetation and microbes.
- Types:- Free Water Surface (FWS) or surface flow wetlands
- Vegetated Submerged Bed (VSB) or subsurface flow wetlands
- Similarities/Differences
- purpose- Seasonality- water budget- unconventional watersheds/inputs
Talking Waters Water Balance Evaluation Other Locations ConclusionWetland Basics
Talking Water Gardens50 Acre Constructed Wetland accepting
effluent from:
ATI-WahChang Wastewater Treatment
Plant
City of Albany/Millersburg Joint
Wastewater Treatment Plant
Primarily designed for temperature
mitigation
Design Flow Rate: Qin= 12.6x106 G/day
Temperature Reduction Goal: ∆T= -5∘ F
Insert Image
Positioning
Within Oregon
and Willamette
Valley
Talking Waters Water Balance Evaluation Other Locations ConclusionWetland Basics
Talking Waters Water Balance Evaluation Other Locations ConclusionWetland Basics
http://www.cityofalbany.net/departments/public-works/wastewater-services/twg/how-twg-works
Talking Waters: Flow Schematic9 cell matrix
Control structures
allow flexibility in
flowpath
Single outlet into
Willamette River
Talking Waters Water Balance Evaluation Other Locations ConclusionWetland Basics
Flow paths6 Distinct Paths
6 Different Treatments
Multiple Solutions
Talking Waters: Typical CellDesign Depth
Emergent Plant Zone: Demerg 0.5’ - 2’
Settling Zones: Dopen 5’ - 12’
No Bottom Lining
Talking Waters Water Balance Evaluation Other Locations ConclusionWetland Basics
http://www.aaees.org/e3competition-winners-2011superiorachievement.php
Plant Cover - Establishment with Time
3/5/2010 7/8/2010 11/16/2011 7/9/2012
Mill Site Construction Phase Grading Complete Cover Expanding
No Emergent Plants No Emergent Plants 22 % Emergent 34 % Emergent
Talking Waters Water Balance Evaluation Other Locations ConclusionWetland Basics
Evaluation Other Locations Conclusion
Current Plant CoverCell # Cell Name Area (Ac.) Area (m2) % Cover
1 West Beaver Marsh 8.83 35734 40
2 Log Pond 5.6 22662 80
3 East Beaver Marsh 4.97 20113 70
4 Lumber Mill 3.16 12788 80
5 Northern Lumber Mill 1.1 4452 30
6 Railroad 1.72 6961 40
7 West Oak 1.68 6799 50
8 Central Oak 2.42 9793 50
9 East Oak 4.72 19101 60
10 East Log Pond 0.57 2307 20
Total Surface Area 34.2 138403 58
Talking Waters Water BalanceWetland Basics
Simplifying Assumptions for CalculationsAggregate as one large “average cell” Aw = 140709 m2
Inflow 75% City + 25% ATI Qin = 47700 m3/day
Constant input temperatures Tin = 20.5∘C
Neglect historical soil modifications Mapped Soil Unit
Restrict water losses to native soil GWo lateral flow only
80% emergent plant cover is achieved Aopen = 28142 m2
Aemerg = 112567 m2
Talking Waters Water Balance Evaluation Other Locations ConclusionWetland Basics
Wetland Water Balance
dV/dt = change in water volume over time (m3/d)
Qi = wastewater inflow rate (m3/d)
QC = catchment runoff rate (m3/d)
QSM = snowmelt rate (m3/d)
QGW = lateral groundwater exchange rate (m3/d)
QB = berm loss rate (m3/d)
QO = outflow rate (m3/d)
P = precipitation (m/d)
ET = evapotranspiration (m/d)
Aw = wetland surface area (m2)
dV/dt = Qi + QC + QSM - QGW - QB - QO + ( P - ET ) * Aw
Talking Waters Water Balance Evaluation Other Locations ConclusionWetland Basics
Albany Climate DataDownloaded from Agrimet website at CRVO station for 1 hour increments
Collected for water year: October 2014 through September 2015
Temperature Solar Radiation
Precipitation Relative Humidity
Average Wind Speed Reference Evapotranspiration
Talking Waters Water Balance Evaluation Other Locations ConclusionWetland Basics
Penman- Monteith EquationTalking Waters Water Balance Evaluation Other Locations ConclusionWetland Basics
EvapotranspirationReference ET from Agrimet station CRVO
ET calculated using Penman-Monteith Equation
Total ET per unit area = 1.375 m/year (calculated), 1.108 m/year (theoretical)
Talking Waters Water Balance Evaluation Other Locations ConclusionWetland Basics
Comparing Calculated and Measured ETTalking Waters Water Balance Evaluation Other Locations ConclusionWetland Basics
Crop ET for wetland plantsCrop coefficient for cattail and bulrush (U. Montana)
Crop coefficient for constructed/maintained marshlands 1.1 (Drexler et al)
Assume 50/50 distribution for cattails and bulrush
Wetlands Kc = 1.12 in dry years and 1.24 in wet years
Calculated Crop ET= 1.54 m/year (Dry Year) and 1.71 m/year (Wet Year)
Talking Waters Water Balance Evaluation Other Locations ConclusionWetland Basics
Plant Type Kc Growth Kc Dormancy # growth months (dry) # growth months (wet)
Cattails 1.6 0.3 5 7
Bulrush 1.8 0.3 5 7
Ground Water
QGWin/out = Qlat / Aw
QGWin/out = groundwater inflow or
outflow
Aw = surface area of constructed
wetland
Qlat = lateral flow into uphill end or out
of downhill end of constructed wetland
Talking Waters Water Balance Evaluation Other Locations ConclusionWetland Basics
Ground Water
Darcy’s equation: Qlat = kiAx
k = hydraulic conductivity
i = hydraulic gradient
Ax = cross sectional area of flow
Malabon Silty clay: k = 9 um/sGroup C type of soil:
- Slow infiltration rate when thoroughly wet.- These consist chiefly of soils having a layer
that impedes the downward movement of water or soils of moderately fine texture or fine texture.
Talking Waters Water Balance Evaluation Other Locations ConclusionWetland Basics
Ground Water
i = (220ft-180ft)/2172 ft = 0.0184Ax = (1.82m)(744 m) =1354 m2
Qlat = 7,075 m3/year
Talking Waters Water Balance Evaluation Other Locations ConclusionWetland Basics
Wetland Water Balance per Year
Term Quantity (m3/year)
Qi 17,410,000
QGW 7,075
Qo 17,272,109
P 180,692
ET (dry year) 311,508
dV/dt = Qi + QC + QSM - QGW - QB - QO + ( P - ET ) * Aw
Addition of wetland has minimal impact to Water Balance
Talking Waters Water Balance Evaluation Other Locations ConclusionWetland Basics
Evaluation of Talking Waters
Primary Goal: “mitigate thermal load of ATI Wah Chang and Albany WWTP
effluents by 150 million Kilocalories/day to protect sensitive fish (salmon)
habitat”
Secondary Goal: Reduce nitrate and ammonia levels in nitrogen-rich effluent
of ATI Wah Chang
Tertiary Goal:Increase biodiversity and provide a recreational/learning site
Talking Waters Water Balance Evaluation Bend, OR ConclusionWetland Basics
Temperature:Experimental DataWinter Flow Rates 2011
Talking Waters Water Balance Evaluation Bend, OR ConclusionWetland Basics
Hart,J. 2012
Talking Waters Water Balance Evaluation Other Locations ConclusionWetland Basics
Temperature: Theoretical Calculation Energy Balance Equation:
Agrimet CRVO Station DataOctober 2014 through September 2015
*Soil Temperature
Air Temperature
Average Wind Speed
Solar Radiation
Actual vapor pressure
Talking Waters Water Balance Evaluation Other Locations ConclusionWetland Basics
Talking Waters Water Balance Evaluation Bend, OR ConclusionWetland Basics Other Locations
Nitrogen SpeciesATI Wah Chang Influent
Nitrate: 7.1-28.1 mg-N/L
Ammonia: 5.3-21.8 mg-N/L
Nitrite: 12.3-20.7 mg-N/L
Albany-Millersburg Water Reclamation Facility Influent
Monthly Average of 2.9 mg/L ammonia,nitrates, and nitrites
Talking Waters Water Balance Evaluation Other Locations ConclusionWetland Basics
Peak Nitrate Concentrations at TW Sites Talking Waters Water Balance Evaluation Other Locations ConclusionWetland Basics
Hart,J. 2012; Huang,T. 2012
Cost analysisLand acquisition, design, construction (wetlands, pump stations, plantings,
flow control structures).
Total Cost: $13.75 million
Annual operational and maintenance costs for wetlands are up to 50% less than traditional options (Kadlec, 2008)
Between 10% and 54% less expensive than alternative temperature mediation based upon City of Woodburn,Or wastewater treatment plant (CH2M Hill, 2010)
approx. 300,000 /year maintenance costs
Talking Waters Water Balance Evaluation Other Locations ConclusionWetland Basics
How would the system function in Bend, OR?Assume same size and design
Same growing season as Albany
but with less precipitation
Talking Waters Water Balance Evaluation Other Locations ConclusionWetland Basics
Evapotranspiration for Bend, OregonReference ET from AgriMet Station BEWO
ET Calculated using Penman-Monteith ET
Total ET per unit area = 0.898 m/year (calculated), 1.093 m/year (theoretical)
Talking Waters Water Balance Evaluation Other Locations ConclusionWetland Basics
Wetlands increase ET by 12% in dry years and 24% in wet years
Kc average 1.18 cattails and 1.05 bulrush for dry years (5 months peak)
Kc average 1.30 cattails and bulrush 1.18 for wet years (7 months peak)
Calculated Crop ET= 1.001 (Dry Year) and 1.114 m/year (Wet Year)
Crop ET for wetland plants in Bend, ORTalking Waters Water Balance Evaluation Other Locations ConclusionWetland Basics
Ground Water
Location: McGrath Bend, OR
Deskamp-Gosney complex: k = 92 um/sGroup A:
- Soils having a high infiltration rate (low runoff potential) when thoroughly wet.
- These consist mainly of deep, well drained to excessively drained sands or gravelly sands.
i = 3ft /2172 ft = 0.0014
Average depth to water table in Northwest
of Bend = 200-400 ft.
Qlat = 5,783 m3/year
Talking Waters Water Balance Evaluation Other Locations ConclusionWetland Basics
Wetland Water Balance for Bend, OR
Term Quantity (m3/year)
Qi 17,410,000
QGW 5,783
Qo 17,303,539
P 40,207
ET (dry year) 140,885
0 = Qi - QGW - QO + ( P - ET ) * Aw
Addition of wetland has minimal impact to Water Balance
Talking Waters Water Balance Evaluation Other Locations ConclusionWetland Basics
Talking Waters Water Balance Evaluation Other Locations ConclusionWetland Basics
Limitations to receiving riverAssume:
Thermal regime similar to Willamette River
Temperature input to wetland at 20.5℃ (up to -2.8℃ change in wetland)
Wetland discharge of 0.55 cms (19.3 cfs)
Receiving river requirements:
Should have peak flows during coldest months
Minimum of 21 - 26 cms (741 - 922 cfs) flow rate
To keep river water temperature change below 0.3℃ (impairment level)
Talking Waters Water Balance Evaluation Other Locations ConclusionWetland Basics
ConclusionsIs talking waters effective?
Theoretically effective at temperature reduction on average
Assumptions are optimistic
How does this change water balance?
Minimal effects on water balance
How would a similar wetland function in a different environment?
Could be moved effectively to other locations, but limits to size and
temperature of receiving stream
Talking Waters Water Balance Evaluation Other Locations ConclusionWetland Basics
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