Too much of a useful thing
Nitrogen and phosphorus are essential nutrients. Problems begin when excessive amounts enter water faster than natural systems can absorb them.
Sources can include fertilizer, manure, pet waste, wastewater, failing septic systems, eroding soil, and some urban runoff. Nutrients can move from small creeks into larger rivers, reservoirs, and coastal waters.
What excess nutrients can cause
- Dense algae and aquatic plant growth.
- Reduced water clarity and recreation.
- Bad tastes and odors in source water.
- Harmful algal blooms.
- Low oxygen when algae die and decompose.
Source control is the cleanest fix. It is usually easier to keep nutrients on the land than to remove them after they enter a creek.
What households and landowners can do
- Test soil before applying fertilizer.
- Keep fertilizer off pavement and away from water.
- Pick up pet waste.
- Maintain septic systems.
- Prevent bare soil and erosion.
- Use vegetation to slow and filter runoff.