Environmental Concerns and Receiving Water
Impacts Associated with Urban Runoff
|
Resource/ Water Use
|
Concern
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Potential Negative Impact On Resource/Water
Use
|
Cause
|
Ground-water
|
Lower Dry-Season Reserves
|
* groundwater pollution *lower
dry-season base flow in watercourses * lower drinking water reserves |
Increased Impervious Catchment Surface Area |
Aquatic Habitat
|
Erosion
|
* physical destruction of habitat |
High Peak Discharges and Runoff Volumes |
Fluctuating Water Levels and Velocities
|
* altered thermal and mixing characteristics *reduced habitat diversity
*erosion |
High Peak Discharges and Runoff Volumes & Low Dry-Season Ground
Water Reserves |
Low Dry-Season Base Flow
|
*elimination of spawning beds
*reduced habitat *reduced
dilution capacity |
Low Dry-Season Groundwater Reserves |
Sedimentation
|
*smothering of bottom communities and spawning beds *filling of stormwater impoundments *transport of particulate-associated pollutants |
Erosion & Suspended Solids |
Turbidity
|
*lower dissolved oxygen *reduced
prey capture *clogging of
fish gills |
Suspended Solids |
Low Dissolved Oxygen
|
*lethal and non-lethal stress to aquatic organisms |
Bio-degradable organic material |
Metals, Organic contaminates, Chlorides
|
*lethal and non-lethal stress to aquatic organisms in water column
and bottom sediments *bioaccumulation
of contaminants and related food chain effects *osmotic stress |
Urban Pollution |
Increased Water Temperature
|
*lethal and non-lethal stress to sensitive cold water aquatic organisms
*increased metal toxicity and hydrocarbon solubility |
Solar Heating of Urban Surfaces & Stored Runoff Water |
Bacteria
|
*diseases of aquatic organisms
*shellfish contamination |
Fecal Contamination |
Eutrophication
|
*algae blooms and nuisance aquatic plant growth *low dissolved oxygen *odours |
Nutrient Enrichment |
Public Water Supply
|
Lower Dry-Season Reserves
|
*reduced water supply |
Lower Dry-Season Groundwater Reserves |
Turbidity
|
*taste *appearance |
Suspended Solids |
Metals, Organic Contaminates, Nitrates, Chlorides
|
*taste *odour *public health |
Urban Pollution |
Bacteria
|
*public health |
Fecal Contamination |
Wildlife Habitat
|
Flooding and Erosion
|
*physical destruction of environment *dewatering and flooding of key habitat areas at critical times
*reduction in streambank cover vegetation |
High Peak Discharges and Runoff Volumes & Sedimentation |
Recreation and Aesthetics
|
Nature Enjoyment
|
*see Aquatic Habitat and Wildlife Habitat |
Se Aquatic Habitat and Wildlife Habitat |
Bacteria
|
*public health in body contact waters *degradation of game fisheries and shellfish beds |
Fecal Contamination |
Agricultural, Residential, and Industrial
Land Use
|
Flooding and Erosion
|
*public safety *damages
to crops and farmland *damages
to building and contents *reduction
of useable land area |
High Peak Discharges and Runoff Volumes & Sedimentation |
Adapted From: Urban Runoff Quality Control Guidelines for British
Columbia. B.C. Ministry of Environment. 1992 |
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