automated water quality project prioritization tool to address tmdls
DESCRIPTION
TRANSCRIPT
Automated Water Quality Project Prioritization Tool
to Address TMDLsRon Novy, Orange CountyJeff Earhart, PE, CPWG
American Public Works Association – April 2-6, 2012
Orange County
+ Population: 1,086,480 (97% urban, 3% rural)+ Land area: 907 sq. mi.+ Water area: 96.7 sq. mi.(10.7%)+ More than 600 named Lakes+ Population density: 1,197 people per square
mile (very high)
Orange County
Lake Management Program Levels:
1. Reactive Management TMDL (Total Maximum Daily Load)
39 TMDL impaired lakes NNC (Numeric Nutrient Criteria)
48 NNC Impaired lakes (under EPA rule)
2. Proactive Management Water quality review, trending, need identification
11 Lakes with declining water quality (not impaired yet)
Orange CountyChallenges:
Funding Orange County has a Stormwater Utility, BUT is set to zero Lake Management allotted $500K per year in CIP
Prioritizing Needs Large vs. small projects BMAP requirements Funding, partnerships & grant availability Removal efficiencies O&M costs Political issues
Changing Conditions Narrative vs. Numeric methodology Changing BMP Removal Efficiencies Changing Loading Rates/Sources
Orange County
Challenges:
Static Needs Assessments / Master Plans
Old methodology “snapshot in time” Based on the parameters at time of creation Changing parameters makes plan quickly out-of-date Can spend $100-$200K every couple of years to update. Keep track of projects & needs separately Hard to project future needs
Orange County
Management Need:
Dynamic Needs Assessments / Master Plan system Live system that can be used year after year GIS based system for easy visualization and queries Updateable to changing needs Updateable to changing parameters Standardized to current conditions Produce a new and current Needs Assessment anytime Perform queries based on particular need
Orange County
Create the Solution
2010 Custom Program Development Initiated2010 Custom Program Development InitiatedOC Lake Management hired BPC/TEK JV to develop a dynamic needs OC Lake Management hired BPC/TEK JV to develop a dynamic needs assessment tool based on specific methodologies and needs:assessment tool based on specific methodologies and needs:
+ GIS based /interactive systemGIS based /interactive system+ Updateable parameter coefficientsUpdateable parameter coefficients+ Track /query loads and needs by desired parameterTrack /query loads and needs by desired parameter+ Evaluate and rank potential projectsEvaluate and rank potential projects+ Track and evaluate completed projectsTrack and evaluate completed projects+ Access supplemental data for each project (studies, plans, photos)Access supplemental data for each project (studies, plans, photos)+ Determine TMDL/BMAP load reduction complianceDetermine TMDL/BMAP load reduction compliance+ Generate a Needs Assessment/Master Plan upon requestGenerate a Needs Assessment/Master Plan upon request
Purpose of Program+ Standardize Pollutant Load Calculations+ Rapid Alternative Analysis Scenario Review+ Identify and Categorize Common BMPs+ Rank Projects Using Decision Matrices+ Ability to Sort Projects Based Multiple Parameters+ Generate Reports
GIS Layers
• Created• Point Projects• Line Projects• Polygon Projects• Project
Watersheds
• Already Exist• Commissioner Districts• Section Township Range• Major Basins• Soils• Land Use• Soils• Streets• TMDL• FDEP WBIDS
GIS Layers
Setting Up a Project
Sorting and Ranking
Report Sheet
Lake Down Watershed
Land Use
Soils
Lake Down Project Information
Lake Down BMP Water Quality Info
Lake Down Capital Costs
Lake Down References Upload
Lake Down Priority Factors
Area-Weighted Runoff Coefficient(C) and Event Mean Concentration (EMC)
+ C = area-weighted runoff coefficient,+ Cn = area-weighted runoff coefficient
for a given land use, n,+ Arean = area (acres) for land use, n,
and HSG, m,+ n = number of different land uses
within the area, and + m = number of different HSGs within
the area.
∑ ∑
∑ ∑
=
=
=n m
mmn
n m
mmnmn
Area
AreaCC
1 1,
1 1,, *
∑ ∑
∑ ∑
=
=
=n m
mmn
n m
mmnmn
Area
AreaCC
1 1,
1 1,, *
+ EMCX = area-weighted EMC for the project for pollutant X(mg/L),
+ n = number of land uses within the area,
+ EMCn = EMC (mg/L) for a given land use, and
+ Arean = area (acres) for a given land use (the total area, A, could also be used here).
( )
∑
∑= n
n
n
nn
X
Area
AreaEMCEMC
1
1
*
Annual Pollutant Loads
+ LX = annual pollutant load (lbs/yr) for pollutant X+ Q = annual runoff volume (ac-ft/yr)+ EMCX = area-weighted event mean concentration (mg/L) for
pollutant X+ 2.72 = a unit conversion value [ (ac-ft/yr)*(mg/L) to lb/yr ].
72.2** XX EMCWeightedQL =
Example Pollutant Load Calculation
Column1 Column2 Area (acres) Column4
Land Use Name TP (mg/l) Area (acres)
EMC * Area
Low-Density Residential 0.190 2 0.380Medium Density Residential 0.306 1 0.306High Density Residential 0.520 2 1.040Commercial 0.170 2 0.340Institutional 0.345 1 0.345
Total 8 2.411Average EMC (mg/l) 0.301
Land Use Soil Group C-Factor Area (acres) Column1
Low-Density Residential A 0.02 2 0.04
Medium Density Residential B 0.1 1 0.1
High Density Residential C 0.3 2 0.6Commercial D 0.43 2 0.86Institutional B 0.24 1 0.24
Total 8 1.84Composite C-Factor 0.23
Example Pollutant Load Calculation Cont
72.2** XX EMCWeightedQL =
Annual Rainfall 50.03 inC-Factor 0.23
Area 8.00 acresFlow (Q) 7.67 ac-ft
EMC 0.30 mg/lLoad (lb/yr) 6.29 lb/yr
Relational Tables+ Pollutant Reduction+ Runoff Coefficients+ Land Use + Event Mean Concentrations+ Land Use Types and Codes+ Decision Matrix Points+ Decision Matrix Weighting
Land Use EMCs Land Use Name TN TP BOD TSS Cu Pb Zn
Low-Density Residential 1.58 0.190 4.4 20.4 0.009 0.002 0.029
Medium Density Residential 2.00 0.306 7.5 33.0 0.018 0.004 0.057
High Density Residential 2.32 0.520 11.3 77.8 0.009 0.006 0.086
Commercial 1.23 0.170 7.6 59.2 0.017 0.006 0.083
Institutional 2.40 0.345 11.3 69.7 0.015 0.006B 0.160
Industrial/Utility 1.23 0.180 7.6 60.0 0.003 0.002 0.057
Transportation Facility 1.64 0.220 5.2 37.3 0.032 0.011 0.120
Pasture Agriculture 3.47 0.616 5.1 94.3 0.013C 0.003C 0.021C
Citrus Agriculture 2.24 0.183 2.6 15.5 0.003 0.001 0.012
Row Crops Agriculture 2.65 0.593 3.8C 19.8 0.022 0.004 0.030
General Agriculture 2.79 0.431 3.8 43.2 0.013 0.003 0.021
Golf Course 2.00 0.306 7.5 33.0 0.018 0.004 0.057
Wetland 1.15 0.074 1.2 7.8 0.0 0.0 0.0
Watered 0.0 0.0 0.0 0.0 0.0 0.0 0.0
Open 1.15 0.074 1.2 7.8 -- -- --
Forest 1.15 0.074 1.2 7.8 -- -- --
BMP Trapping Efficiencies for TP BMP %
Off-line Retention 0.25 treatment volume 40
Off-line Retention 0.50 treatment volume 62
Off-line Retention 0.75 treatment volume 75
Off-line Retention 1.00 treatment volume 84
On-line Retention 0.25 treatment volume 30
On-line Retention 0.50 treatment volume 52
On-line Retention 0.75 treatment volume 65
On-line Retention 1.00 treatment volume 74
Wet Pond 0.5 TV, 7 day residence time 40
Wet Pond 1.0 TV, 14 day residence time 60
Combination Swale/Wet Pond 92
Dry Detention 10
Baffle Box 10
Nutrient Baffle Box (Second Generation) 25
Catch Basin Inserts / Inlet Filters 5
BMP %
Catch Basin Inserts / Inlet Filters* 1.98
Grass Swales 35
Infiltration Trench 52
Porous Pavement 0.5 52
Concrete Grad Pavement 0.5 52
Street Sweeping (semi-weekly) 20
Street Sweeping (semi-weekly)* 2.81
Street Sweeping (weekly) 15
Street Sweeping (weekly)* 1.4
Street Sweeping (biweekly) 10
Street Sweeping (biweekly)* 0.7
Stormceptor 10
CDS 5
Public Education 5
Wetlands 10
Media Filter System 36
Alum 89*lbs/curb mile/yr
Factor WeightsFactor Weight
Pollutant Removal % 30
TMDL Compliance % 30
Funding Availability 5
Land Availability5
Public Support 5
Downstream Benefits 10
BMAP Process 5
Life Cycle Cost 10
Pollutant Reduction Percentage Point Value
Value (%)Per Pollutant
Points
0-5 0
6-25 1
26-50 3
51-11 5
TMDL Compliance Point ValueValue (%) Points
0-5 2
6-10 3
11-15 4
16-20 5
21-25 6
26-30 7
31-35 8
36-40 9
41-100 10
Funding and Land Availability Point Value Non-County
Contribution/ValuePoints
0 – 10% 1
>10 – 25% 2
>25 – 50% 3
>50 – 75% 4
>75 – 100% 5
Land for Specific Project/Value
Points
No Available Land 0
Privately Owned (Unknown)
2
Privately Owned (Willing Seller)
3
County Owned 5
Public Support and Downstream Benefit Point Value Public Support/Value Points
Opposed Project -5
Neutral or Unknown 0
Strong Demand 5
Downstream Benefits/Value
Points
No Outfall 0
Drainwell 1
Downstream has lower water quality
2
Downstream has higher water quality
4
OFW, Preserve, or Other 5
Street Sweeping and Catch Basin Pollutant Load Estimation
+ Source: PM and Nutrient Load Recovery, Credits and Costs for MS4 Maintenance Activities by University of Florida Engineering School of Sustainable Infrastructure and Environment, Environmental Engineering Sciences Department, John Sansalone, PhD
+ The primary objective is a Florida based “yardstick” or metrics allowing an MS4 to quantify nutrient (N and P) loads through separation then recovery of particulate matter (PM) for common urban hydrologic functional units (HFU)
1. Pavement systems cleaning (pavement street sweeping)2. Catch basins (inlets)3. “BMP” (the most utilized and cleaned BMPs in MS4)
Participating Florida MS4s
Project Sampled a Diversity of “BMPs”
TN Results by Land Use and HFU
Cost $/Pound: PM, TP, TN Separation or Recovery
Example: Street Sweeping PM, TP, TN Recovery
Report Information
Street Sweeping Area
Street Sweeping Area
Street Sweeping Based on Lane Mile+ 5.93 Swept Miles+ 12.48 TP lb/mile/yr+ 73.97 TP lb/year
removed
Street Sweeping Based on Percent Removal+ 5.93 Swept Miles+ 20% TP removal
Rate+ 208.25 TP lb
removed
Florida-Based Distribution of P (as TP)
Conclusions
+ Monitor Compliance with TMDL Goals
+ Support and Document Needs and Results for Council or Commission
+ Active Report
+ Removal Efficiencies Customizable to a Specific Project
+ Quick and Standardized Alternative Analysis
+ Find the Best Project that Meets Grant Requirements or Funding Needs
Ron Novy, Orange [email protected]
Jeff Earhart, PE, CPWG,[email protected]