Watershed Diagnostics for Improved Adoption of Management Practices: Integrating Biophysical and Social Factors
1. Watershed Diagnostics for Improved
Adoption of Management Practices:
Integrating Biophysical and Social Factors
PAUL T. LEISNHAM
DEPT. ENVIRONMENTAL SCIENCE & TECHNOLOGY,
COLLEGE OF AGRICULTURE & NATURAL RESOURCES,
UNIVERSITY OF MARYLAND
NIWQP: 2012-51130-20209; $631,500
2. Talk Outline
1. Background
2. Impacts of climate change on pollution Critical Source
Areas (CSAs)
3. Impacts of climate change on Best Management
Practice (BMP) effectiveness
4. Competing views on water pollution and BMPs
among stakeholders
3. Paul Leisnham,
Socio-Ecology
Dan Boward,
MD-DNR
Ecology
Tom Hutson & Nicole Barth,
Extension
David Lansing,
UMBC
Sociology
Adel Shirmohammadi,
Hydrology
Victoria Chanse, Amanda
Rockler & numerous
students
Extension & Sociology
Hubert Montas,
Diagnostic Tools
Jaison Rekenberger,
Diagnostic Tools
Daniel Schall,
UMBC
Sociology
Julianna
Brightman,
Sociology
4. Develop, implement, and evaluate a cross-disciplinary
approach for watershed management that considers
both technical (biophysical) and social factors
Objectives
1. Evaluate community attitudes towards water resources and
identify barriers to BMP adoption
2. Develop a Diagnostic Decision Support System (DDSS) to
identify CSAs and prescribe targeted BMPs
3. Develop and evaluate strategies for increasing awareness and
behaviors towards water quality to increase BMP adoption
5. Tom Fisher, Horn Point Laboratory, UMCES
Algae and turbidity are increasing
over time, and summer bottom DO
is decreasing
Little improvement in Chesapeake
Bay in past 40 years
6. 0
0.2
0.4
0.6
0.8
1
1.2
5/1/87 5/6/87 5/11/87 5/16/87 5/21/87 5/26/87 5/31/87
Date
Precipitation(inches/day)
Study Area Spatial Database
Pollutant
Transport
Model
Diagnosis
Expert System
Pollutant Export Hot Spots BMP Allocation Plan
Prescription
Expert SystemExcess Export Causes
Pollutant Hot Spots
Excess Export
Causes
Bio-
Dynamic
Models
DDSS Development
Components: GIS, Models, Expert Systems
Models: SWAT (SUSTAIN, AQUATOX, FIBI, EPA BASINS)
Expert Systems: MATLAB (predicate calculus to decision
trees)
• DDSS will rank environmental
causes to pollution and
prescribe a BMP allocation
plan
• Geo-referenced biophysical
and land management data
• Simulate watershed
responses to selected
stressors
• Identify CSAs & prescribe
appropriate BMPs
• More “bang for the buck”
7. Climate Change Forecasts for the
Northeastern United States
↑ Elevated concentrations of atmospheric CO2
↑ Elevated mean temperature
↑ Increased mean rainfall
↑ Shift in seasonal rainfall patterns
o Wetter spring
o Drier late summer
↑ Increases in extreme weather events
9. Model Construction and Analysis
Software Purpose and Progression
ArcGIS Spatial Data Analysis
(Graphics and Database)
ArcSWAT Model development
SWAT input file Generation
SWAT-CUP Model calibration
(SUFI-2 Method)
SWAT Experimental engine
(SWAT.exe)
Model Calibration
Warm-up (3 yrs): 1/1/1990 to 12/31/1992
Calibration Period (15 yrs): 1/1/1990 to 12/31/2004
Data Type Characteristics
Topography/DEM 10 meter
Landuse/Land Cover NLCD 2006 HRU
Soils NRCS SSURGO
Weather (Calibration) 3 stations NCEP CFSR
Flow, Nutrients and
Sediment
1 USGS Gauging
Station Greensboro
Climate Change
GFDL-CM2.1
CMIP3 (B1, A1B, A2)
(Mid and End Century)
Model Validation
Warm-up (2 yrs): 1/1/2005 to 12/31/2006
Validation Period (6 yrs): 1/1/2005 to
12/31/2010
Downscaled climate predictions from global model based around 3 IPCC
scenarios that lead to low, medium, and high future levels of CO2
10. Definition of a Critical Source Area (CSA)
Rank SurQ (mm H20) TSS (tonnes/ha/yr) TN (kg/ha/yr) TP (kg/ha/yr)
Top 10% >406 >1.03 >24 >1.9
Top 20% >359 >0.73 >16 >1.6
Top 10%: Value for which the top ~770 HRUs is separated from the other 7705 HRUs
Top 20%: Value for which the top ~1540 HRUs is separated from the other 7705 HRUs
An area that exports a target pollutant at concentrations
significantly above average
Always defined a watershed area (or HRU) a CSA if it exported
a given pollutant at these fixed thresholds
12. Watershed Response: Baseline and Climate
Change Scenarios
400
450
500
550
600
650
700
750
800
850
B ASELINE M ID C ENTUR Y
(2 0 4 6 -2 06 4)
END C ENTUR Y
(2 0 8 1 -2 10 0)
STREAMFLOW
(MM/YR)
B1 A1B A2
10
12
14
16
18
20
22
B ASELINE M ID C ENTUR Y
(2 0 4 6 -2 06 4)
END C ENTUR Y
(2 0 8 1 -2 10 0)
TOTALNITROGEN
(KG/HA/YR)
B1 A1B A2
0.7
0.8
0.9
1.0
1.1
1.2
1.3
1.4
1.5
B ASELINE M ID C ENTUR Y
(2 0 4 6 -2 06 4)
END C ENTUR Y
(2 0 8 1 -2 10 0)
TOTALPHOSPHORUS
(KG/HA/YR)
B1 A1B A2
0.4
0.5
0.6
0.7
0.8
0.9
1.0
1.1
B ASELINE M ID C ENTUR Y
(2 0 4 6 -2 06 4)
END C ENTUR Y
(2 0 8 1 -2 10 0)
SEDIMENT
(MG/HA/YR)
B1 A1B A2
13. Surface Run-off & Total Suspended
Solids
Present Day CSAs SRES A2 End Century CSAs
25-30% ↑ rainfall
3.9X ↑ 3.0X ↑
14. Present Day CSAs SRES A2/A1B End Century CSAs
Nitrogen & Phosphorous
25-30% ↑ rainfall
3.7X ↑ 2.5X ↑
17. Targeting Dense CSAs of Today
Residual CSA Density with Baseline BMP Design Subjected to Current, A1B and A2 Climate Conditions
TMDL targets met 64%-143% above TMDL Targets
18. Targeting Dense CSAs of the Future
Residual CSA Density with A2 BMP Design Subjected to Current, A1B and A2 Climate Conditions.
TMDL targets met TMDL targets met
20. Two dominant discourses
from Interviews and Q-sort
Scientists and environmental
professionals: Stressed the role of
agriculture in water degradation,
& importance of regulating all
adverse land-use practices
Farmers and agricultural
extension agents: Stressed the
importance of industry-driven
regulation, local knowledge &
were skeptical of “outside”
knowledge, including science.
Axes of Regulation and Cultural Knowledge
Legend
Increasing Regulation
Deregulation
Outside
knowledge
Local
knowledge
21. Highlights Summary
1. Climate change will likely increase areas that export
excessive levels of pollutants
2. Targeting CSAs works, but a BMP allocation plan based
on today’s CSAs fail to meet TMDL goals
3. We need a BMP allocation plan based on future climate
scenarios demanding greater community-based
participation
4. We need to overcome existing divergent viewpoints
among stakeholders on pollution and its management
22. Final Work: Integrating Social Dimensions
into DDSS
KAP surveys with farmers and urban residents.
23. Example Research-Education-
Extension Outputs
3 journal papers in press or advanced peer-review
o 2 in Special Climate Change edition of Transactions of the ASABE
3 journal articles in prep.
12 presentations at national conferences
o Best student poster (Renkenberger) at 2014 AWRA Annual Meeting
2 MS students graduated
6 undergraduates trained
Graduate class developed (“Watershed Ecosystem Sustainability”)
4-H EcoStewards program developed (850 participants)
o 4-H youth and adult water quality education aids
Adult water quality in-service trainings for educators (190 participants)
27. Extension Outreach
12
2
14
40
19
3
29
5
20
57
42
3
0
10
20
30
40
50
60
Pamphet Youtube Workshop Extension Govt Other
Numberofresponses
Delivery Method
BMP information delivery of 59
respondent farmers
'Existing Delivery (n=90)
'Desired Delivery (n=156)
59
12
0
50
100
Interested Not interested
Numberoffarmers
Interest
Farmer interest of additional
information on BMPs (n=71)
28. Polarizing statements
There is very strong evidence that agriculture is the single largest source of
nitrogen, phosphorous and sediment going into the Chesapeake Bay.
Water problems like Pfiesteria should not be blamed on chicken manure
because of all of the sewage being pumped into the bay right in the port of
Baltimore. Pollutants like this in the bay aren’t from the farmers.
The most effective regulators are people who came up from the industry of
whatever it is they’re regulating because they understand what actually
happens.
Large companies like Perdue control all aspects of growing chickens, they
should pay for Agricultural Best Management Practices for farmers.
29. 1 2 3 4
Water problems like Pfiesteria
should not be blamed on
chicken...
The most effective regulators
are people that come up from
industry...
There is very strong evidence
that agriculture is the single
largest source of nitrogen...
Large companies like Perdue
control all aspects of growing
chickens...
Strongly
Disagree
Disagree Agree Strongly
Agree
Farmer (n = 66)
responses as part
of survey
These statements stimulated the
strongest responses and were the
most polarizing, from 26
stakeholder interviews and Q-sort
analysis
Paired T-TEST: T = -11.60, p < 0.0001
30. Biophysical Modeling
Once we have a working model…
1. We can use best available science to find Critical Source Areas (CSAs)
2. We don’t have to physically install BMPs (now or in the future), saving money
3. We can use the model to test BMP configurations that will achieve TMDL targets
Effects of Climate Change
B1
A2
A1B
SWAT
(Soil Water and
Assessment Tool)
Land Use/Cover
Topography
Soils
Weather
Other
Flow Prediction
Sediment Loadings
Nutrient Loadings
Water Balance/Availability Nutrient Output x BMP Removal Eff (%) = TMDL Attainment
31. BMP Design and Targeting Methods
Typical Design
Strategy
Baseline Model
(SWAT)
Apply targeting method
and calculate BMP
efficiencies
Repeat for A2 and A1B
scenarios using baseline
conditions
Future Proof
Design Strategy
End Century Model
(SRES A2 SWAT)
Apply targeting method
and calculate BMP
efficiencies
Repeat for Baseline and
A1B scenarios using A2
conditions
Examine effect of climate
change on BMP
implementation
Compare/Evaluate Two
Targeting Methods:
• CSA Based (Dense CSAs)
• Non-CSA Based (Land Use)
Apply Generic SWAT BMP
Removal Required to Meet Bay
TMDL Targets
Scenario TSS TN TP
Baseline 33% 45% 23%
B1 63% 64% 49%
A1B 69% 70% 53%
A2 71% 67% 57%
32. Results: In-Stream Validation, Monthly
Points falling on SWAT generated
streams were correlated by
month
1.Reach Export Correlation
◦ Discharge is significant in the same month
as well as the month prior
◦ TP is significant in the same month of
sampling
◦ TSS and TN are significant in month prior to
sampling
2. Two month lag was considered but may
be anomalous due to infrequent
sampling
Constituent IBI (%) Habitat Index (%)
Month Discharge (cm/s) -0.83 -0.86
Sediment (mg/L) 0.38 -0.16
Total N (mg/L) 0.80 0.35
Total P (mg/L) -0.83 -0.52
Month-1 Discharge (cm/s) -0.79 -0.98
Sediment (mg/L) -0.60 -0.67
Total N (mg/L) -0.32 -0.66
Total P (mg/L) 0.05 0.52
Month-2 Discharge (cm/s) -0.12 -0.19
Sediment (mg/L) 0.20 -0.36
Total N (mg/L) 0.82 0.39
Total P (mg/L) -0.91 -0.58
33. 𝑇𝑀𝐷𝐿 = 𝑊𝐿𝐴 + 𝐿𝐴 + 𝑀𝑂𝑆
Point Sources + Non-Point Sources + Margin of Safety
Motivation: EO 13508 and Regulation
TSS, TN and TP
Editor's Notes
My name is Paul Leisnham from the University of Maryland
I want to thank Jim, Nancy and all the organizers for this conference, and it’s a pleasure to kick off the project talks today.
It’s with some intrepidation that I give a talk after communication experts, but I’ll try my best to showcase some highlights from this project.
It was funded by the NIWQP in 2012 and still has until 2017 to complete, and has a total budget of just over $600K.
In my talk, I am going to address three main highlights so far, after a very brief background to the project.
CSAs are watershed areas that export target pollutants at rates significantly higher than others,
As you may have gleaned from the outline, this is a integrated research-extension-education project and cross-disciplinary in nature.
My expertise is as a socio-ecologist, but we have personnel with expertise in hydrology and the development of diagnostic tools, sociology and education and extension.
I have highlighted Jasion and Daniel who are you Masters students supported by the project and who did much of the work, along with numerous undergraduates.
The highlights in this talk will center on the first two objectives.
The focus of our work as been the Choptank watershed on the Delmarva Peninsula, and in particular a sub-watershed called the Greensboro watershed which is predominantly agricultural.
The Greensboro watershed is characteristic of many watersheds in the Chesapeake Bay basin in that we are seeing little improvement in water quality despite considerable research and outreach to reduce non-point source pollutants from agricultural practices, such as sediment, nitrogen and phosphorous.
Water quality data for the Greensboro watershed over the 40 years shows…
Our approach to addressing such water degradation is to build a diagnostic decision support system tools to help watershed managers develop BMP allocations plans.
The diagnostic tool will…There are three main sub-components to the : 1. Geo-referenced… of the study area. 2. Bio-dynamic models that…. 3. Set of two expert systems that will…
With this approach we can get the most bang for the buck.
Details:
Why is a hotspot a hotspot? Is it because of topography, is it because of soil depth? Is it because of type of agricultural practice?
ID appropriate practice for each hotspot.
Data: Hydrology, water quality, ecosystem health
Source: ARS, MBSS, student-led surveys (Leisnham)
Methods: compare values, trends, orders of magnitude, timing.
Nash-Sutcliffe and Pearson coefficients.
Sensitivity analysis.
Field inspection for hot-spot verification.
Correlate predicted water quality with BIBI from field observations.
However, when considering BMP implementation a complicating factor is climate change. The Northeast has experienced and will continue to experience a range of impacts…and of particular importance to this talk the greatest is quite possibly increases in extreme weather events.
In particular, the northeast has already experienced a dramatic increase in the amount in very heavy events (i.e., top 1% of daily events). We may expect CSAs identified under current climate may no longer be sufficient to control NPS pollution with future climate change. Thus, we also need to identify CSAs and prescribe BMPs under different climate change scenarios.
Precipitation and Temperature are the primary forcers driving watershed response.
North Eastern United States: % change in amount of precipitation falling in top 1% of heaviest daily rainfall events.
Temperature changes as predicted by SRES B1, A1B and A2 climate scenarios (Working Group III).
This slide simply has some details of the data and model construction, calibration, validation based on observations at the gauging station.
This study used downscaled climate predictions from global GFDL CM2.1 based around the 3 socio-economic development scenarios of the IPCC Special Report on Emission Scenarios (SRES) that lead to low, medium and high future levels of atmospheric CO2.
To note, the Greensboro watershed consisted of a total of 7705 distinct HRUs based on the combinations environmental data.
Detail:
Used past weather to calibrated so that output in watershed model looked at watershed output in real life.
The B1 storyline is characterized by a world that tends toward a service based economy and technologies that are resource efficient. The A1B scenario reflects a balance between fossil and non-fossil fuel sources, in combination with rapid economic and technological growth worldwide. The A2 storyline is one where economies and social boundaries remain heterogeneous into the future and economic and technological growth are slower than for B1 and A1B.
Changes in land use not taken into account. PPT does change and
And we defined a CSA as…..
Our breakpoint was the top 10% or 20% of watershed areas, or HRUs, that exported a given constituent, and then always defined areas a CSA if they exported pollutants at these fixed excessive levels
This is important to identify for focusing our BMP implementation. We want to do this as effectively and efficiently as possible. I should note here that the point of defining CSAs is to reduce the amount of land area targeted by less-strategic placement of BMPs.
Not based on TMDLs or water quality. Ranking is only relative to present day model.
All Scenarios: 25-30% more rain
Changes between scenarios are also affected by rainfall intensity
Produces:
SurQ: 56% - 90% 1.60x
TSS: 79% - 132% 1.67x
TN: 56% - 88% 1.57x
TP: 52% - 80% 1.54x
Over the next two slides I am going to show you the worst-case increase in land area considered a CSA based on our fixed thresholds.
We expect to see a 25-30% increase in rainfall under the A2 emissions scenario and this leads to massive increases excessive surface runoff and sediment.
Keep in kind that I’m showing large increases with the worst case scenario by increases under milder emissions scenarios at mid-century also see large increases.
Details:
Average annual concentration and total export
Percent Change in Area
SurQ: 21% - 81% 3.9x
TSS: 18% - 45% 2.5x
Percent Change in Export
SurQ: 31% - 89% 3x
TSS: 46% - 81% 1.5x
Worst case emissions scenario for nitrogen pollution is A1B which just nearly as much total rainfall but less extreme events which allows more infiltration and subsurface flow which leaches more Nitrogen
Average annual concentration and total export
Percent Change in Area
TN: 11% - 41% 3.7x
TP: 13% - 32% 2.46x
Percent Change in Export
TN: 31% - 72% 2.3x
TP: 39% - 66% 1.70x
To assess the impacts of climate change on BMP effectiveness we first want to consider how we will prescribe BMPs when we have four constituent pollutants.
One method is to apply BMPs to watershed areas, or HRUs, with multiple CSAs. Here I am showing you maps with 3 CSAs overlaid each other, and areas are given a CSA Denisty. We have baseline scenario and the two higher emissions scenarios at end of century, which have more critically dense areas.
Ok So what may we expect when we allocate targeted BMPs?
A single HRU can be a CSA for more than one pollutant. These HRUs are more critically dense than other HRUs. Hence a CSA density.
Critical Break Values are the same as defined earlier. They are fixed.
BMPs at the 20% CBV need to be applied to all CSAs
What we found is that if we implement BMPs on dense CSAs of today, we may STILL end up with significant proportions of watershed that are still critically dense CSAs in the future, under climate change, and TMDL targets are missed. BMP progress is lost due to climate change.
When relating BMP effectives to TMDL targets, the take home message is that we will meet TMDL targets if we ignore climate change but miss TMDL targets by 64-143% under the worst case emissions scenario
Keep in mind, that we are just focusing on TSS, N, P b/c everywhere would be a CSA with Surface runoff.
Using this strategy we target 31% of the watershed area.
Details:
Based on Stationary design we target 31% of the watershed area
BMP Eff% TSS = 61%; TN = 79%; TP = 43%
However, Future Scenarios show that in the future we will still end up with 64%-143% above TMDL Targets
Concluding Statement for this slide: BMP progress is lost due to climate change
In comparison, if we target critically dense CSAs under high emissions climate change conditions, we address CSAs now and into the future and TMDL targets are met. Under this strategy we are targeting 58% of the watershed, which is more than the 31% of the prior targeting strategy, but we achieve much better outcomes. But by needing to target are larger proportion of the watershed we demand greater stakeholder commitment.
Details:
A future design with a 20% threshold requires targeting 58% of the land area
BMP efficiencies of 82%, 74% and 72% for TSS, TN and TP respectively
TMDLs are met now and in the future (Except for TN >100%)
This slide shows the results of a Q-sort and factor analysis of stakeholder attitudes from stakeholder interviews. Q-sort is a social science instrument to understand relationships between various stakeholder viewpoints on a topic that are gathered form semi-structured interviews. For brevity, I won’t go into details of our interviews as part of this project but highlight two key elements in interpreting this figure:
There were two dominant discourses from stakeholder interviews. Regulation and Knowledge Source.
Each symbol represents an individual participant and symbols close to together represent similar attitudes. We can see a clear, statistically significant division, between stakeholder groups.
[note that while farmers may be considered environmentalists, we considered “environmentalists” here as those people who did not farm but worked on environmental issues (e.g., scientists, environmental professionals)
Scientists emphasized agricultural run-off was a significant contributor of water degradation in the region but wanted to independent regulation all land uses that contribute to water degradation.
Farmers didn’t load as high on that discourse, and while acknowledging some regulation was necessary preferred it to come from within the industry and only if it did not interfere with their ability to secure a livelihood. Farmers on the other hand emphasized local knowledge as being important.
Details:
From these interviews two dominant discourses emerged: Regulation and Knowledge Source. Each symbol represents an individual participant and symbols close to together represent similar attitudes. We can see clear, statistically significant division, between stakeholder groups. Scientists emphasized agricultural run-off was a significant contributor of water degradation in the region but wanted to independent regulation all land uses that contribute to water degradation. Farmers didn’t load as high on that discourse, and while acknowledging some regulation was necessary preferred it to come from within the industry and only if it did not interfere with free enterprise to secure a livelihood. Farmers on the other hand emphasized local knowledge as being important. This work was led by our colleague, Dr. David Lansing from UMBC.
Differences of opinions between environmentalist and farmers are not a surprise to many of you and we have to acknowledge that this is a challenge that we have to overcome to properly address watershed management. These results are impt b/c they highlight that the type of knowledge and how it is delivered is important, and that stakeholder attitudes are likely shaped by a wide range of influences, underlying values, and ideologies.
The interviews revealed clear differences in stakeholder perceptions of water resources with two discourses, regulation and knowledge source, being particularly dominant. [READ SLIDE]
26 semi-structured interviews were conducted and Q methods were applied to transcripts to analyze responses.
34 statements were pulled from the interviews that covered a selection around one or two topics of what the interviewees stated.
Interviewees and additional research subjects were revisited are then asked conduct a Q survey. The respondents must place the statements into a normalized distribution (individual sorts), ranking the statements from “most strongly
agree” which equals positive (+4) to “most strongly disagree” which equals negative (–4).
After pulling statements, each was assigned to one of two different domains and subcategories or sub-themes within each domain: 1) What is an Agricultural Best Management Practice? and 2) What drives land-use decision
making on the Eastern Shore?
I performed a principal components factor analysis. Two factors that were identified as significant at distinguishing groups of respondents: Regulation and Construction of Knowledge.
Causes of pollution
Who should regulate
Role of Poultry Industry
One of the last research steps of this project is integrating social data into the DDSS in the form of a BMP adoption sub-model. We want to estimate what the likelihood that stakeholders are likely to implement BMPs given their demographic, socio-economic and cultural conditions. We have gathered quantities data to address this in surveys and currently completing that sub-model.
data
We can also plan targeted education strategies to specific demographic groups that may have knowledge or attitudes that are barriers to BMP adoption, and we could model how changes in knowledge and behavior affect water quality.
To do this we have administered in-depth face-to-face KAP surveys with over 72 farmers and 84 residents in the wider Choptank watershed. These numbers may not seem high but they are very sufficient to detect relationships between demographic variables, metrics of knowledge and attitude and BMP practice of the participants.
We are in the process of developing this sub-model but I will simply share two results.
Some god news from the surveys, is that the majority of surveyed farmers are interested in receiving information on BMPs.
Some god news from the surveys, is that the majority of surveyed farmers are interested in receiving information on BMPs, and their preferred sourse of delivery is from extension agents and govt professionals. interThe second results was that farmers were generally receptive to receiving additional information on BMPs, and that their most desired delivery is via Extension Agents
To give you a better sense of the diverse viewpoints, I want to share with you the statements that were most polarizing between stakeholders.
As a part of Q-sort, these were statements were taken directly from interview transcripts, and then ranked as being most strongly agreed or disagreed among 30 such statements then presented to a second set of stakeholders.
Note that Pfiesteria are heterotrophic dinoflagellates that has been associated with harmful algal blooms and fish kills
The first is that the survey results were generally consist with the interview in that there was divergent agreement on the most polarizing statements. Surveyed farmers agreed with the two most strongly supported statements from the interviews, and disagreed with the statements that interviewed farmers disagreed with
How can watershed modeling be useful for adaptation and climate resilience?
When we talk about climate change we are either talking about adaptation or mitigation. Here we will focus on adaptation.
Physical, chemical, biological changes
Distributed parameter model
Where do we implement our tools?
BMP’s are tools
Tracking vulnerability into the future.
This is a time sensitive problem
How is the landscape changed by climate change?
Policy makers need to know what to expect
We have the Chesapeake bay model.
Computer Modeling
Pros
Identify areas that need BMPs
Test BMP application
Close the “monitoring gap”
Cons
Hydrology is imprecise
BMP modeling assumes average effectiveness
Limited ability to represent the “real world”.
Distributed Problems and Distributed Solutions
Vulnerable areas need to be identified
Vulnerable areas will change with a variable climate
BMPs can be expensive
BMPs take time to implement
BMP effectiveness changes with climate change
Purpose of Targeting Methods: Minimize or optimize balance between BMP area placement and BMP efficiency.
Table is minimum BMP efficiency: Assumes 100% aerial placement. This minimizes efficiency
CSA Based: Computationally simpler but with over design
These are the results of a time series correlation analysis between sampling points (IBI and HI vs Discharge, TSS, TN and TP). The same analysis is done but shifted by up to two months prior to the time the sample was taken (by month not by day as these are monthly average SWAT output). We see that HI is similarly significant but slightly different than IBI. HI is the physical condition of the habitat with regard to bank erosion/stability and vegetative cover.
We see some correlation in the Month-2 scenario but it is to be taken with a grain of salt. All sampling points are taken only once a year so there is insufficient information to rule this out as an anomaly. However, there may be a sort of IBI and HI “decay rate” for which benthic life will respond over a time period longer than a month to various kinds of rainfall events. There is a hint of this in month-2 (Orange box) for HI looking at the negative correlations (which is good) for discharge and sediment. However, this would be difficult to determine using monthly average as it could be just spilled over correlation from data points taken very close to the beginning or end of the month of sampling.
Lastly, phosphorus may have a much more immediate effect which is why correlation skips a month and is negative again in month-2. We would need data from months-3 and -4 to determine if this is a natural fluctuation response or just an anomaly.
Executive Order and the Clean Water Act of 1972: Fishable, swimmable and drinkable
Point Sources: Industry outfalls, untreated poultry farming litter, Wastewater treatment plants
Non-Point Sources: Agriculture, urban and suburban open spaces, impervious areas
This is our current approach to addressing water quality problems here in the US.
TMDLs issued at the federal level are important because watersheds cross county, state and even country boundaries.
What is missing? A consideration of climate change in the WIP framework