Download - Reservoir and Lake Nutrient Criteria
![Page 1: Reservoir and Lake Nutrient Criteria](https://reader035.vdocuments.mx/reader035/viewer/2022062314/5681329d550346895d993daa/html5/thumbnails/1.jpg)
Reservoir and Lake Nutrient Criteria
A Different ApproachA Different Approach
D.V. Obrecht, J.R. Jones & M.K. Knowlton – MU Limnology
![Page 2: Reservoir and Lake Nutrient Criteria](https://reader035.vdocuments.mx/reader035/viewer/2022062314/5681329d550346895d993daa/html5/thumbnails/2.jpg)
UMBRELLA APPROACH
1) Reference reservoirs and lakes – 75th percentile
2) All reservoirs and lakes – 25th percentile
3) EPA’s 304(a) criteria
![Page 3: Reservoir and Lake Nutrient Criteria](https://reader035.vdocuments.mx/reader035/viewer/2022062314/5681329d550346895d993daa/html5/thumbnails/3.jpg)
Oxbow lakes (n=12)
TP = 212 ug/L
TN = 1.56 mg/L
Reservoirs (n=135)
TP = 45 ug/L
TN = 0.73 mg/L
![Page 4: Reservoir and Lake Nutrient Criteria](https://reader035.vdocuments.mx/reader035/viewer/2022062314/5681329d550346895d993daa/html5/thumbnails/4.jpg)
Reservoir TP (µg/L) range of geomeans
Maysville (n=10) 182 116 – 300
Grindstone (n=5) 147 90 - 218
Unionville (n=10) 98 68 - 155
Long Branch (n=20) 48 30 - 115
Viking (n=16) 26 19 - 40
Forest (n=19) 23 14 - 44
![Page 5: Reservoir and Lake Nutrient Criteria](https://reader035.vdocuments.mx/reader035/viewer/2022062314/5681329d550346895d993daa/html5/thumbnails/5.jpg)
STEP APPROACH
Designated Use
Impairment of use
Algal biomass
Nutrient levels
Criteria level
![Page 6: Reservoir and Lake Nutrient Criteria](https://reader035.vdocuments.mx/reader035/viewer/2022062314/5681329d550346895d993daa/html5/thumbnails/6.jpg)
![Page 7: Reservoir and Lake Nutrient Criteria](https://reader035.vdocuments.mx/reader035/viewer/2022062314/5681329d550346895d993daa/html5/thumbnails/7.jpg)
Drinking Water Supply
Impairments
-taste and odor
-clogging of filters
-algal toxins
![Page 8: Reservoir and Lake Nutrient Criteria](https://reader035.vdocuments.mx/reader035/viewer/2022062314/5681329d550346895d993daa/html5/thumbnails/8.jpg)
There may be too many factors that influence water quality and too much variability within and among systems to allow for the setting of a single set of criteria to be used by
the state for regulation.
![Page 9: Reservoir and Lake Nutrient Criteria](https://reader035.vdocuments.mx/reader035/viewer/2022062314/5681329d550346895d993daa/html5/thumbnails/9.jpg)
![Page 10: Reservoir and Lake Nutrient Criteria](https://reader035.vdocuments.mx/reader035/viewer/2022062314/5681329d550346895d993daa/html5/thumbnails/10.jpg)
![Page 11: Reservoir and Lake Nutrient Criteria](https://reader035.vdocuments.mx/reader035/viewer/2022062314/5681329d550346895d993daa/html5/thumbnails/11.jpg)
![Page 12: Reservoir and Lake Nutrient Criteria](https://reader035.vdocuments.mx/reader035/viewer/2022062314/5681329d550346895d993daa/html5/thumbnails/12.jpg)
EPA allows some flexibility:
…(states can) develop their own criteria which reflect more locally representative conditions.
…prioritize their waters…..Such an approach should include a mechanism for evaluating the sensitivity of all waters…considering current and expected land use…
EPA memorandum, Nov. 14, 2001
![Page 13: Reservoir and Lake Nutrient Criteria](https://reader035.vdocuments.mx/reader035/viewer/2022062314/5681329d550346895d993daa/html5/thumbnails/13.jpg)
A Different Approach!
![Page 14: Reservoir and Lake Nutrient Criteria](https://reader035.vdocuments.mx/reader035/viewer/2022062314/5681329d550346895d993daa/html5/thumbnails/14.jpg)
A lake is a reflection of its watershed.
![Page 15: Reservoir and Lake Nutrient Criteria](https://reader035.vdocuments.mx/reader035/viewer/2022062314/5681329d550346895d993daa/html5/thumbnails/15.jpg)
0 5 20 40 60 80
100
200
5
10
5
r = 0.622
25
50
Cropland (%)
To
tal
Ph
osp
ho
rus
(µg
/L)
![Page 16: Reservoir and Lake Nutrient Criteria](https://reader035.vdocuments.mx/reader035/viewer/2022062314/5681329d550346895d993daa/html5/thumbnails/16.jpg)
A reservoir is also a reflection of its watershed,
and the intensity of that reflection is dictated by
hydrology.
![Page 17: Reservoir and Lake Nutrient Criteria](https://reader035.vdocuments.mx/reader035/viewer/2022062314/5681329d550346895d993daa/html5/thumbnails/17.jpg)
Regression model resultsEquation r2
TP = 4.27 + 0.36 %crop 0.62
TP = 5.53 + 0.33 %crop – 0.50DH 0.73
TP = 5.20 + 0.35crop% - 0.37 DH + 0.12 FI 0.77
DH is dam height, a surrogate from reservoir morphology
FI is flushing index
![Page 18: Reservoir and Lake Nutrient Criteria](https://reader035.vdocuments.mx/reader035/viewer/2022062314/5681329d550346895d993daa/html5/thumbnails/18.jpg)
Volume 100
outflow 100
outflow 200
inflow 100
inflow 50
inflow 200
Volume / Inflow = Residence Time (years)
outflow 50
Volume 100
Volume 100
RT = 2 years
RT = 1 years
RT = .5 years
![Page 19: Reservoir and Lake Nutrient Criteria](https://reader035.vdocuments.mx/reader035/viewer/2022062314/5681329d550346895d993daa/html5/thumbnails/19.jpg)
1 3 5 7 9
Residence Time (years)
0.0
0.2
0.4
0.6
0.8
Cro
p L
and
Use
(p
rop
ort
ion
wat
ersh
ed)
![Page 20: Reservoir and Lake Nutrient Criteria](https://reader035.vdocuments.mx/reader035/viewer/2022062314/5681329d550346895d993daa/html5/thumbnails/20.jpg)
0 1 2 3 4
Residence Time (years)
0.0
0.2
0.4
0.6
0.8
Cro
p L
and
Use
(p
rop
ort
ion
wat
ersh
ed)
= TP < 20 g/L
![Page 21: Reservoir and Lake Nutrient Criteria](https://reader035.vdocuments.mx/reader035/viewer/2022062314/5681329d550346895d993daa/html5/thumbnails/21.jpg)
0 1 2 3 4
Residence Time (years)
0.0
0.2
0.4
0.6
0.8
Cro
p L
and
Use
(p
rop
ort
ion
wat
ersh
ed)
= TP 20 - 50 g/L
![Page 22: Reservoir and Lake Nutrient Criteria](https://reader035.vdocuments.mx/reader035/viewer/2022062314/5681329d550346895d993daa/html5/thumbnails/22.jpg)
0 1 2 3 4
Residence Time (years)
0.0
0.2
0.4
0.6
0.8
Cro
p L
and
Use
(p
rop
ort
ion
wat
ersh
ed)
= TP 50 - 75 g/L
![Page 23: Reservoir and Lake Nutrient Criteria](https://reader035.vdocuments.mx/reader035/viewer/2022062314/5681329d550346895d993daa/html5/thumbnails/23.jpg)
0 1 2 3 4
Residence Time (years)
0.0
0.2
0.4
0.6
0.8
Cro
p L
and
Use
(p
rop
ort
ion
wat
ersh
ed)
= TP 75 - 100 g/L
![Page 24: Reservoir and Lake Nutrient Criteria](https://reader035.vdocuments.mx/reader035/viewer/2022062314/5681329d550346895d993daa/html5/thumbnails/24.jpg)
0 1 2 3 4
Residence Time (years)
0.0
0.2
0.4
0.6
0.8
Cro
p L
and
Use
(p
rop
ort
ion
wat
ersh
ed)
= TP > 100 g/L
![Page 25: Reservoir and Lake Nutrient Criteria](https://reader035.vdocuments.mx/reader035/viewer/2022062314/5681329d550346895d993daa/html5/thumbnails/25.jpg)
0 1 2 3 4
Residence Time (years)
0.0
0.2
0.4
0.6
0.8
Cro
p L
and
Use
(p
rop
ort
ion
wat
ersh
ed)
![Page 26: Reservoir and Lake Nutrient Criteria](https://reader035.vdocuments.mx/reader035/viewer/2022062314/5681329d550346895d993daa/html5/thumbnails/26.jpg)
![Page 27: Reservoir and Lake Nutrient Criteria](https://reader035.vdocuments.mx/reader035/viewer/2022062314/5681329d550346895d993daa/html5/thumbnails/27.jpg)
Proportion crop
Short Res. Time
Med. Res. Time
Long Res. Time
> 40%
20 – 40%
10 – 20%
1 – 10%
< 1%
![Page 28: Reservoir and Lake Nutrient Criteria](https://reader035.vdocuments.mx/reader035/viewer/2022062314/5681329d550346895d993daa/html5/thumbnails/28.jpg)
Proportion crop
Short Res. Time
Med. Res. Time
Long Res. Time
> 40% 116 ug/L 75 ug/L 47ug/L
20 – 40% 97 ug/L 80 ug/L 53 ug/L
10 – 20% 59 ug/L 54 ug/L 33 ug/L
1 – 10% 40 ug/L 27 ug/L
< 1% 17 ug/L
![Page 29: Reservoir and Lake Nutrient Criteria](https://reader035.vdocuments.mx/reader035/viewer/2022062314/5681329d550346895d993daa/html5/thumbnails/29.jpg)
Residence Time (months)
0
50
100
150
To
tal
Ph
osp
ho
rus
(ug
/L)
>12 6-12 <6
>40% 20% - 40% 10% - 20% 4% - 10% crop =
>10 >106-10 6-10<6 <6 <2>2
![Page 30: Reservoir and Lake Nutrient Criteria](https://reader035.vdocuments.mx/reader035/viewer/2022062314/5681329d550346895d993daa/html5/thumbnails/30.jpg)
Can we use agriculture to classify reservoirs?
Can we use agriculture to classify reservoirs?
USGS photo
![Page 31: Reservoir and Lake Nutrient Criteria](https://reader035.vdocuments.mx/reader035/viewer/2022062314/5681329d550346895d993daa/html5/thumbnails/31.jpg)
Reservoirs were built into landscapes that had already been altered.
No Restoration
Water quality in a reservoir is a function of morphology/hydrology and location within the landscape.
![Page 32: Reservoir and Lake Nutrient Criteria](https://reader035.vdocuments.mx/reader035/viewer/2022062314/5681329d550346895d993daa/html5/thumbnails/32.jpg)
7,600 – 34,000 ac
34,000 – 58,000 ac
58,000 – 87,000 ac
87,000 – 169,000 ac
Harvested acres of corn, 1920
30 counties
26 counties
36 counties
22 countiesBetween 11% and 21% of total Missouri land surface dedicated to just corn production in 1920!
![Page 33: Reservoir and Lake Nutrient Criteria](https://reader035.vdocuments.mx/reader035/viewer/2022062314/5681329d550346895d993daa/html5/thumbnails/33.jpg)
Missouri’s reservoirs >10 acres in sizeYear completed # %
1800-1920 122 8
1920-1940 267 18
1940-1960 68 5
1960-1980 909 61
1980-1995 121 8
![Page 34: Reservoir and Lake Nutrient Criteria](https://reader035.vdocuments.mx/reader035/viewer/2022062314/5681329d550346895d993daa/html5/thumbnails/34.jpg)
0 1 2 3 4
Residence Time (years)
0.0
0.2
0.4
0.6
0.8
Cro
p L
and
Use
(p
rop
ort
ion
wat
ersh
ed)
Protect
Improvements possible
Limited potential
![Page 35: Reservoir and Lake Nutrient Criteria](https://reader035.vdocuments.mx/reader035/viewer/2022062314/5681329d550346895d993daa/html5/thumbnails/35.jpg)
This approach allows the state to:
-Identify and protect the reservoirs that have low watershed impacts.
-Identify and focus efforts on the reservoirs that have higher nutrient concentration than expected, given watershed land use and hydrology.
-Gauge the potential for successful nutrient reduction by looking at the factors that control in-reservoir nutrient concentrations. And focus limited resources ($$) on those reservoirs where improvements can be made.