Minnehaha Creek TMDL Project Update June 7, 2012 Minnehaha Creek - - PowerPoint PPT Presentation

▶
minnehaha creek tmdl
SMART_READER_LITE
LIVE PREVIEW

Minnehaha Creek TMDL Project Update June 7, 2012 Minnehaha Creek - - PowerPoint PPT Presentation

Sep 25, 2023 48 likes •262 views

Minnehaha Creek TMDL Project Update June 7, 2012 Minnehaha Creek Watershed District Office Minnehaha Creek TMDL Discussion Overview Discussion Overview CIP Summary CIP Summary Li k Linkage Analysis A l i Quick re-cap Allocations

slide-1
SLIDE 1

Minnehaha Creek TMDL

Project Update

June 7, 2012 Minnehaha Creek Watershed District Office

slide-2
SLIDE 2

Minnehaha Creek TMDL

Discussion Overview Discussion Overview

CIP Summary CIP Summary Li k A l i

Quick “re-cap”

Linkage Analysis Allocations

Potential Options

Allocations

slide-3
SLIDE 3
slide-4
SLIDE 4

Linkage Analysis

Quick “Re Quick “Re-Cap” Cap”

Bacteria Bacteria

slide-5
SLIDE 5

Linkage Analysis

Total Phosphorus

Quick “Re Quick “Re-Cap” Cap”

Total Phosphorus

slide-6
SLIDE 6

Linkage Analysis

Reduction Needs Reduction Needs

Parameter 2001-2011 Average Target Reduction

  • E. coli (#/100mL)

301 1 126 58% Total Phosphorus (µg/L) 70.9 40 2 44%

3

p (µg ) 50 3 29% Notes:

1 Average values reflect geometric mean, consistent with WQS. 2 Minnesota Rule 7050 2 Minnesota Rule 7050. 3 MCWD Lake Hiawatha water quality goal.

slide-7
SLIDE 7

Linkage Analysis

Grays

Assessment Points Assessment Points

Grays Bay Lake Hiawatha West 34th Excelsior McGinty 32nd Ave Browndale BD to COL COL to Hiawatha

McGinty

slide-8
SLIDE 8

Linkage Analysis

Bacteria

Reduction Needs Reduction Needs

Group

High Moist Mid Dry Low

Bacteria

  • Grays Bay
  • A

McGinty (Minnetonka)

  • B
  • W. 34th (Minnetonka, SLP, Hopkins)
  • 25%

4%

C

Excelsior (SLP, Hopkins) 12% 35% 55% 76% 45%

D

Browndale

(SLP, Edina)

  • (

)

E

BD to COL (Edina, Minneapolis) 19% 32% 16% 46% 47%

F

COL to Hiawatha (Minneapolis) 40% 54% 58% 73% 68%

slide-9
SLIDE 9

Linkage Analysis

Watershed Loading Watershed Loading

slide-10
SLIDE 10

TMDL Development

TMDL Report -- Required Elements

Regulatory Regulatory Framework Framework

TMDL Report Required Elements

Applicable WQ Standards Loading Capacity Source Assessment Allocations Seasonal Variation Seasonal Variation Margin of Safety

TMDL

W A

WLA

A MOS

TMDL = WLA Point Sources + WLAMS4 + LA + MOS

slide-11
SLIDE 11

Watershed Loading

Drainage Area Perspective Drainage Area Perspective

slide-12
SLIDE 12

Allocations

Potential Options Potential Options

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

slide-13
SLIDE 13
slide-14
SLIDE 14

Subwatershed Groups

Approximate Composition Approximate Composition

City A B C D E F

Plymouth

5%

Wayzata

3%

Minnetonka

87% 75%

Minnetonka

87% 75%

  • St. Louis Park

16% 59% 25%

Hopkins

7% 36% 7%

Edina

4% 60% 60%

Minneapolis

37% 100%

slide-15
SLIDE 15

Potential Allocations

Equal Percent Reduction Equal Percent Reduction

Applied at all points

Group

Allocation (lbs) Reduction lbs %

Applied at all points

(lbs) lbs %

  • Grays Bay

1,279

  • A

McGinty (Minnetonka) 640 269 29.6%

B

  • W. 34th (Minnetonka, SLP, Hopkins)

584 246 29.6%

C

Excelsior (SLP, Hopkins) 727 305 29.6%

D

Browndale

(SLP, Edina)

464 195 29.6%

( )

E

BD to COL (Edina, Minneapolis) 579 243 29.6%

F

COL to Hiawatha (Minneapolis) 498 210 29.6% Needed Reduction: 1,468 lbs

slide-16
SLIDE 16

Potential Allocations

Equal Percent Reduction Equal Percent Reduction

Applied at all points Applied at all points

slide-17
SLIDE 17

Unit Area Loading

Concept Concept

Load divided by Area Load divided by Area

Group Area Rate Group

(acres) (lbs/acre) A McGinty 3,493 0.260 B W 34th 5 101 0 163 B

  • W. 34th

5,101 0.163 C Excelsior 1,998 0.517 D Browndale 1,426 0.462 E BD to COL 2,171 0.379 F COL to LH 2,504 0.283

slide-18
SLIDE 18

Unit Area Loading

Area Export Coefficient Area Export Coefficient

Load divided by Area Load divided by Area

slide-19
SLIDE 19

Potential Allocations

Area Export Coefficient Area Export Coefficient

Based on total area

(0.209 lbs / acre)

Group

Allocation (lbs) Reduction lbs %

Based on total area (0.209 lbs / acre)

(lbs) lbs %

  • Grays Bay

1,279

  • A

McGinty (Minnetonka) 730 177 19.5%

B

  • W. 34th (Minnetonka, SLP, Hopkins)

1,067

  • 237
  • 28.5%

C

Excelsior (SLP, Hopkins) 418 614 59.5%

D

Browndale

(SLP, Edina)

298 361 54.7%

( )

E

BD to COL (Edina, Minneapolis) 454 368 44.8%

F

COL to Hiawatha (Minneapolis) 523 185 26.1% Needed Reduction: 1,468 lbs

slide-20
SLIDE 20

Potential Allocations

Impervious Cover Weighting Impervious Cover Weighting

Based on Impervious Area

(0.448 lbs / acre)

Group

Allocation (lbs) Reduction lbs %

Based on Impervious Area (0.448 lbs / acre)

(lbs) lbs %

  • Grays Bay

1,279

  • A

McGinty (Minnetonka) 595 312 34.4%

B

  • W. 34th (Minnetonka, SLP, Hopkins)

886

  • 56
  • 6.8%

C

Excelsior (SLP, Hopkins) 530 502 48.6%

D

Browndale

(SLP, Edina)

279 379 57.7%

( )

E

BD to COL (Edina, Minneapolis) 549 273 33.2%

F

COL to Hiawatha (Minneapolis) 650 58 8.2% Needed Reduction: 1,468 lbs

slide-21
SLIDE 21

Potential Allocations

“Combination” Approach “Combination” Approach

Average of Area Export & Impervious

Group

Allocation (lbs) Reduction lbs %

Average of Area Export & Impervious

(lbs) lbs %

  • Grays Bay

1,279

  • A

McGinty (Minnetonka) 663 244 26.9%

B

  • W. 34th (Minnetonka, SLP, Hopkins)

976

  • 145
  • 17.6%

C

Excelsior (SLP, Hopkins) 474 558 54.1%

D

Browndale

(SLP, Edina)

289 370 56.2%

( )

E

BD to COL (Edina, Minneapolis) 502 320 39.0%

F

COL to Hiawatha (Minneapolis) 587 121 17.1% Needed Reduction: 1,468 lbs