Post on 20-Jan-2016
transcript
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