Minnehaha Creek Lake Hiawatha TMDL Project Update April 16, 2013 - - PowerPoint PPT Presentation

Minnehaha Creek – Lake Hiawatha

TMDL Project Update

April 16, 2013 Minnesota Pollution Control Agency Office

Minnehaha Creek TMDL

Discussion Overview

BMP Targeting

Total phosphorus

Allocations

Quick overview

Draft TMDL Report Implementation

Bacteria

TMDL Development

Data Driven Approach

Figure 3-1

Quick “Re-Cap”

Bacteria

Data Driven Approach

Figure 3-2

Total Phosphorus

Quick “Re-Cap”

Figure 3-3

Data Driven Approach

Reduction Needs

TMDL Targets

Parameter 2001-2011 Average Target Reduction

• E. coli (#/100mL)

301 1 126 58.1% Total Phosphorus (µg/L) 70.9 2 50 29.5% Notes:

1 Average values reflect April- Oct. geometric mean,

consistent with WQS.

2 Value reflects growing season average (June-Sept),

consistent with site-specific criteria.

Table 3-3

Bacteria

Linkage Analysis

Loading & Response

Figure 5-13

Group

High Moist Mid Dry Low

• Grays Bay
• A

McGinty

• B
• W. 34th
• 25%

4%

C

Excelsior 12% 35% 55% 76% 45%

D

Browndale

• E

Browndale to Chain of Lakes 19% 32% 16% 46% 47%

F

Chain of Lakes to Lake Hiawatha 40% 54% 58% 73% 68%

H

Lake Hiawatha to mouth 30% 12%

• 15%

6%

Bacteria

Reduction Needs

Linkage Analysis

Table 5-5

Categorical Allocation Explicit “Margin of Safety”

Bacteria Allocations

TMDL Development

Overall Target

MnDOT has individual WLA WLA assigned to all MS4s Duration curve framework Set at watershed outlet

Summary

Duration Curve Zone High Moist Mid Dry Low

LOADING CAPACITY

857 412 153 41.0 13.7

WLA -- TOTAL

610.0 295.7 107.8 28.77 8.23

Categorical MS4 WLA

588.2 285.1 103.9 27.74 7.94

Mn DOT MS4 WLA

21.8 10.6 3.9 1.03 0.29

LA -- TOTAL

161.3 75.1 29.9 8.13 4.10

Non-MS4 stormwater

129.3 62.7 22.9 6.10 1.74

Upstream Boundary

32.0 12.4 7.0 2.03 2.36

Margin of Safety (10%)

85.7 41.2 15.3 4.10 1.37

Table 6-2

Bacteria Allocations

TMDL Development

Watershed Loading

Linkage Analysis

Phosphorus

Figure 5-14

Watershed Estimates

Unit Area Loads + Other Sources

Group Area

(acres)

Rate

(lbs/acre)

Seasonal

(pounds)

Cumulative

(pounds)

• Grays Bay
• 1,279

1,279 A McGinty 3,494 0.260 908 2,187 B

• W. 34th

5,103 0.163 827 3,014 C Excelsior 1,998 0.500 1,033 4,047 D Browndale 1,427 0.378 539 4,586 E BD to COL 2,172 0.378 821 5,407 F COL to LH 2,504 0.283 709 6,116 G LH Direct 1,195 0.283 347 6,463

Table 5-6

Phosphorus Loading

Linkage Analysis

Subwatershed Group Load

(pounds per growing season)

Upstream

A/B C D E F G

MS4 Stormwater

1,141.2 904.3 490.9 791.0 690.3 337.6

Wastewater Facilities

33.8 4.6

Non-MS4 Stormwater

593.8 94.9 48.1 30.0 18.7 0.7

Atmospheric

4.1

Upstream

1,279

TOTAL EXISTING

1,279 1,735 1,033 539 821 709 347

Existing Phosphorus Loads

Summary of Table 5-9

Linkage Analysis

MLCCS Data

Combination approach WLAs Non-MS4 stormwater estimates

Figure 2-3

Total Phosphorus Site Specific Criteria 2001-2011 Average Reduction Needs Loading Capacity Percent TP

Concentration

(μg/L)

50 70.9 29.5% = (70.9-50) 70.9

Load

(pounds/season)

6,463 1,907 4,556

Table 6-3

TMDL Development

Loading Capacity Determination

Phosphorus

TMDL Development

1,907 pounds

Figure 6-1

Phosphorus Reduction

Equal Percent Reduction Area Export Coefficient Impervious Cover “Combination” Approach

Methods Considered

Phosphorus Allocations

Subwatershed Group Load

(pounds per growing season)

Upstream

A/B C D E F G

MS4 Stormwater

911 349.6 228.9 426.4 508.5 244.3

Wastewater Facilities

33.8 4.6

Non-MS4 Stormwater

474 38.8 22.4 16.2 13.8 0.5

Atmospheric

4.1

Upstream

1,279

TOTAL ALLOCATIONS

1,279 1,385 422.2 251.3 442.6 522.3 253.5

TOTAL EXISTING

1,279 1,735 1,033 539 821 709 347 Consolidated Table 6-5

Summary

Phosphorus Allocations

Subwatershed Group Load

(pounds per growing season)

A/B C D E F G

MS4 Stormwater

Existing 1,141.2 904.3 490.9 791.0 690.3 337.6 Allocation 911.0 349.6 228.9 426.4 508.5 244.3 Reduction 20% 60% 53% 46% 26% 28%

Non-MS4 Stormwater

Existing 593.8 94.9 48.1 30.0 18.7 0.7 Allocation 474.8 38.8 22.4 16.2 13.8 0.5 Reduction 20% 60% 53% 46% 26% 28% Combined Summary of Table 5-9 and Table 6-5

Group Summary

Phosphorus Reductions

Total Phosphorus Load Reduction

(percent)

Existing Allocation Reduction

Plymouth

24.5 19.6 4.9 20%

Wayzata

13.0 10.4 2.6 20%

Minnetonka

872.7 696.7 176.0 20%

• St. Louis Park

725.8 332.8 393.0 54%

Hopkins

383.8 170.5 213.3 56%

Edina

841.4 424.4 416.9 50%

Minneapolis

1,285.1 884.8 400.4 31%

Hennepin Co.

52.9 34.2 18.7 35%

Mn DOT

156.1 95.4 60.6 39%

Summary

Phosphorus Allocations

Table 6-6

Group

NPDES Wastewater Facility Allocation (lbs) C

• St. Louis Park GWP

Reilly Tar Site: #002

26.4

• St. Louis Park GWP

Reilly Tar Site: #001

6.3

• St. Louis Park WTP

1.1 G

Kwong Tung Foods

4.6

Individual NPDES Facilities

Point Source Allocations

Based on DMR data

Stormwater BMPs

Bacteria

Implementation

Volume control / infiltration BMPs Illicit discharge detection & elimination program Pet waste management Street sweeping Illicit discharge ordinances Filtration BMPs

Implementation Actions

Storm Water Management

Pollutant reduction through:

• Treatment
• Flow / Volume Management

BMP Targeting & Optimization

Characterization Costs

General Process

Available Practices

BMP Targeting & Optimization

Management Options Opportunities

Multi-scale Analysis

Reasonable Assurance Pilot

Land Use Patterns

Prioritize

Impervious Cover Estimates

Total Area Impervious Estimate MC-54 31 31% MC-55 140 62% MC-56 46 67% MC-57 54 85%

Impervious Surfaces

Subwatershed Example

MLCCS Class Land Use Category

% of MLCCS Class IC

Impervious Surface

(percent of total impervious cover) Parking Road Driveway Sidewalk Roof

E / F

Commercial Retail

65 50 5 5 40

Office

25 45 5 5 45

Institutional School, Hospital

10 40 5 5 50

C / D

Commercial

10 45 5 5 45

Apartment/Condo

10 35 10 5 50

Residential <15 years

15 32 10 10 48

15-30 years

30 41 10 10 39

>30 years

35 45 27 3 25

B

Transportation

10 100

Residential <15 years

25 32 10 10 48

15-30 years

30 41 10 10 39

>30 years

35 45 27 3 25

BMP Opportunities

Treatment Train

Routing Source Areas

Level of Implementation Sensitivity

BMP Opportunities