Effects of Nutrient Enrichmenton Rivers and Streams

Ohio EPA

2006

Mandate to Restore Polluted Waters

FEDERAL WATER POLLUTION CONTROL ACT[As Amended Through P.L. 107–303, November 27, 2002]

SEC. 101. (a) The objective of this Act is to restore and maintainthe chemical, physical, and biological integrity of the Nation’swaters.

Leading Causes of Impairment2000 Ohio Water Resources Inventory

0 200 400 600 800 1000 1200 1400

Habitat Alterations

Siltation

Organic Enrichment

Nutrients

Flow Alteration

Metals

2000

1998

1996

1222

932.7

783.2

575.9

537.3

413.5

922.1

547.4

762.7

305.6

313.3

379

847.2

754.2

931.2

228

314.8

226.1

Miles Impaired By Cause

AssessmentCycle

Effects of Nutrient Enrichment On Streams

• Increased Algae Growth• Wide Swings in Dissolved Oxygen

– fish need at least 4.0 mg/l

• Simplified Biological Communities– fewer types of fish and bugs but more of them– fish kills

• Habitat a Strong Modifier– Shading, Assimilative Capacity

Habitat Destruction and Nutrient EnrichmentEffects on Stream Fish Community

Healthy Fishery Degraded Fishery

Good Habitat(Shading, Better Nutrient Processing, More Living Places)

Poor Habitat(Full Sunlight, Boom and Bust Production, Fewer Living Spaces)

Historic Range of Smallmouth BassTrautman’s Fishes of Ohio

Viable Smallmouth Bass Fisheries

Nutrient StudySampling Locations 2004 & 2005

2004

2005

USGS ‘05

2006 Basins

Findings from Nutrient Study2004 & 2005

0.0100.100

1.000

PHOSPHORUS

0

5

10

15

20

25

D.O

. S

win

g

0 60 120 180Canopy

0

5

10

15

20

25

D.O

. S

win

g

D.O. Swings As Related to TP and Canopy

Gross Nutrient EnrichmentStillwater River

0

5

10

15

20

25

0 2000 4000 6000 8000Time

D.O

. m

g/l

9/12–14/05

Buffers and Habitat Quality

Nothing here to filter pollution Bank erosion

Landuse and Nutrient Enrichment

0 10 20 30 40 50 60 70 80 90 100Percent Agricultural

0.010

0.100

1.000

Ph

osp

ho

rus

0 10 20 30 40 50 60 70 80 90 100Percent Agricultural

0

5

10

15

20

25

D.O

. Sw

ing

Average Phosphorus Concentrations Around Ohio

Little or No DataBackgroundNormalEnrichedPolluted

Stream Quality and Density of CAFOs

Darke

MercerAuglaize

Very Poor

Poor

Fair

Good

Excellent

Stream Quality

Managing the Landscape to Manage Nutrient Loads

• Streams need wide buffers– provide shading

• cooler temperature• limit algae growth

– filter pollutants• allow sediment to drop out• vegetation take up nutrients• accidents do happen, need margin of safety

• Good Physical Habitat– increase processing of nutrients– where drainage needed, use natural channel designs

• Wetlands or Riparian for Tile Drainage– tiles by-pass riparian zone