AVERAGE ANNUAL SEDIMENT AND NUTRIENT LOADS

PHASE II OFTHE NON-TIDAL ANACOSTIA MODEL

Interstate Commission on the Potomac River Basin

March 8, 2004

MODEL SEGMENTATION

PHASE I--PHASE II COMPARISON

PHASE I PHASE II

Simulation Period 1988-1995 1996-2000

Land Use MOP 1990 PG County 2000

Montgomery Co.

Calibration Data CAMP

OWML (NW Only)

LTCP

(1999-2000)

Calibration Target STORM CONC. STORM LOADS

TARGET STORMWATER CONCENTRATIONS

(mg/l)

Residential Commercial Industrial

BOD5 16.85 16.72 16.07

NO3 0.595 0.589 0.728

TKN 1.52 2.81 1.14

TP 0.408 0.193 0.249

TSS 118 123 169

SIMULATED AVERAGE ANNUAL SEDIMENT LOADS (tons/yr)

0

2,000

4,000

6,000

8,000

10,000

12,000

14,000

16,000

18,000

Co

mm

ercia

l

Co

rn

Fo

rest

Ha

y

Ind

ustria

l

LD

R

HD

R

Pa

sture

Ed

ge

-of-S

trea

m

PS

In-stre

am

Tota

l

NE NW LBC

SIMULATED AVERAGE ANNUAL BOD LOADS (lbs/yr)

-400,000

-200,000

0

200,000

400,000

600,000

800,000

1,000,000

1,200,000

Com

mercial

Corn

Forest

Hay

Industrial

LDR

HD

R

Pasture

Edge-of-S

tream

PS

In-stream

Total

NE NW LBC

SIMULATED AVERAGE ANNUAL TP LOADS (lbs/yr)

0

10,000

20,000

30,000

40,000

50,000

60,000

Com

mercial

Corn

Forest

Hay

Industrial

LDR

HD

R

Pasture

Edge-of-S

tream

PS

In-stream

Total

NE NW LBC

SIMULATED AVERAGE ANNUAL AMMONIA LOADS (lbs/yr)

0

2,000

4,000

6,000

8,000

10,000

12,000

14,000

16,000

18,000

Com

mercial

Corn

Forest

Hay

Industrial

LDR

HD

R

Pasture

Edge-of-S

tream

PS

In-stream

Total

NE NW LBC

SIMULATED AVERAGE ANNUAL NITRATE LOADS (lbs/yr)

-40,000

-20,000

0

20,000

40,000

60,000

80,000

100,000

120,000

140,000

160,000

180,000

Com

mercial

Corn

Forest

Hay

Industrial

LDR

HD

R

Pasture

Edge-of-S

tream

PS

In-stream

Total

NE NW LBC

SIMULATED AVERAGE ANNUAL ORGANIC NITROGEN LOADS (lbs/yr)

0

50,000

100,000

150,000

200,000

250,000

Com

mercial

Corn

Forest

Hay

Industrial

LDR

HD

R

Pasture

Edge-of-S

tream

PS

In-stream

Total

NE NW LBC

ESTIMATED AVERAGE ANNUAL SEDIMENT LOADS (tons/yr)

0

10,000

20,000

30,000

40,000

50,000

60,000

70,000

80,000

CBP Phase 4.3 TAM/WASP Phase I Phase II Model

ESTIMATED AVERAGE ANNUAL BOD LOADS (lbs/yr)

0

500,000

1,000,000

1,500,000

2,000,000

2,500,000

TAM/WASP Phase I Phase II Model

NW BRANCH BOD STORM LOADS (lbs)SIMULATED VS. OBSERVED

0

10,000

20,000

30,000

40,000

50,000

60,000

0 10,000 20,000 30,000 40,000 50,000 60,000

Model

Ob

serv

ed

ESTIMATED AVERAGE ANNUAL NUTRIENT LOADS (lbs/yr)

0

200,000

400,000

600,000

800,000

1,000,000

1,200,000

1,400,000

1,600,000

1,800,000

TP NH4 NO3 ORN TN

CBP Phase 4.3 TAM/WASP Phase I Phase II Model

SIMULATED LOAD AS PERCENT OBSERVED LOAD

ORIGINAL

PHASE I

PHASE I

PHASE II

PARAMETERS

TSS 337% 142%

TP 70% 47%

TN 625% 37%

OBSERVED SEDIMENT CONCENTRATIONS

0

100

200

300

400

500

600

700

800

900

1000

0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%

Percent Excedence

TS

S (

mg

/l)

Phase 1 Phase 2

OBSERVED TP CONCENTRATIONS

0

0.2

0.4

0.6

0.8

1

1.2

0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%

Percent Excedence

TP

(m

g/l)

Phase 1 Phase 2

OBSERVED TKN CONCENTRATIONS

0

0.2

0.4

0.6

0.8

1

1.2

0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%

Percent Excedence

TP

(m

g/l)

Phase 1 Phase 2

THE REPORT IS AVAILABLE AT:

http://www.potomacriver.org/info_center/publications.htm

NEXT STEPS

CONTACTS

Ross Mandel, ICPRB

rmandel@icprb.org

Rou Shi, ICPRB

roushi@icprb.org