The purpose of this project was to evaluate the …...Thermal regime similar to Willamette River Temperature input to wetland at 20.5 (up to -2.8 change in wetland) Wetland discharge

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.

https://www.cityofalbany.net/departments/public-works/wastewater/twg

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


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 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



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


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


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


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


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


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


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)


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)


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


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.


Ground Water

i = (220ft-180ft)/2172 ft = 0.0184Ax = (1.82m)(744 m) =1354 m2

Qlat = 7,075 m3/year


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


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


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 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


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


How would the system function in Bend, OR?Assume same size and design

Same growing season as Albany

but with less precipitation


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)


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


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



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)


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


Documents

The purpose of this project was to evaluate the …...Thermal regime similar to Willamette River Temperature input to wetland at 20.5 (up to -2.8 change in wetland) Wetland discharge