| Changes |
Impact |
| Changes in
stream hydrology |
- increase
in magnitude/frequency of severe floods
- decrease
in base flows
- decrease
in groundwater recharge
- increase
in flow velocities during storms
|
| Changes in
stream morphology |
- channels
widen
- downcutting
of streambeds, erosion of streambanks
- reduction
in hydraulic capacity die to shifting bars of coarse
sediments
- loss of
pool/riffle structure
|
| Changes in
stream water quality |
- increase
in nutrient loads (organic and inorganic nitrogen, phosphorous)
causing algal growth
- bacterial
contamination
- increase
in sedimentation affecting the food chain
- increase
or decrease in pH levels
- deposits
of heavy metals and other toxic chemicals onto stream
sediments
- increase
in hydrocarbon concentrations
- increase
in water temperatures due to heat reflected from impervious
surfaces
|
| Changes in
stream ecology |
- reduction
in diversity of aquatic organisms
- sedimentation
creates barriers to fish migration
- loss of
in-stream habitat structures (pool and riffle sequences,
overhead cover)
- decline
in amphibian populations
|
