Impacts of Land Development on

Oregon’s Waters

2001

Looking at the whole watershed

Forestry

Urban development

Agriculture

Septic systems

Impacts

Land development can cause…

Polluted Polluted waterwater

Loss of fish Loss of fish and wildlife and wildlife

habitathabitat

Altered Altered water water flowsflows

Impacts

Types of water pollution

Point source– Industrial outflow

Non-point source – “Polluted runoff”– “Diffuse pollution”– “Runoff pollution”

Impacts

Oil & grease contamination

Heavy metal contamination

Chemical components of pollution

Pesticide & herbicide contamination

Increased harmful bacteria

Increased nutrients

Increased oxygen demanding materials

Impacts

Physical components of pollution

Increased sediment input

Increased temperatures

Impacts

Stormwater hotspots

A land use or activity that produces higher concentrations of trace metals, hydrocarbons or priority pollutants than normally found in urban runoff.

Impacts

Impaired or destroyed fish and wildlife habitat

Changes in species diversity and abundance

Changes in physical structures

Photo Copyright Oregon Sea Grant 1999

Impacts

Aquatic habitat:

“Properly Functioning Conditions”

Temperature in natural range Enough dissolved oxygen Clear enough to see food and

breathe Clean enough for food web to

function Clean and complex enough for

spawning and rearing habitat

Impacts

Altered water flows

Increased flood peaks

More frequent flooding

Lower dry weather flow

Loss of stream complexity

Center for Watershed Protection, Copyright 1999

Water balance

Impacts

Flooding and urban development

Impacts

Impervious surface cover as an indicator

– Rooftops

– Transport Systems

• Parking lots• Streets• Sidewalks• Driveways• Cul de sacs

Impacts

Where do we stand?

Local impervious surface cover Local building trends Pollution problems Habitat loss

Impacts

Prevention works:taking action locally

Limit impervious surface across the watershed

Treat stormwater Restrict high risk activities in

sensitive areas Create buffers around

streams, wetlands, and shore lands

Encourage tree preservation and native vegetation

University of Connecticut, NEMO