Threats to Watershed Health

Watershed Threats in History
There is evidence of people around Monterey Bay as early as 6,000 years ago. Some of the first settlers were the Ohlone Indians. They used the bay as a resource for food. They also used extensive fire control to make area for large meadows. These meadows provided habitat for small prey such as rabbits. The Spanish came to Monterey Bay in 1770 and a mission was established in Carmel. It was this establishment that eventually lead to cattle ranching in the eighteen hundreds. Cattle ranching was the first major degradation to the environment around Monterey Bay. It changed the ecosystem dramatically by disrupting the composition of the local wildlife populations. Logging, especially of the Redwoods, also became popular in the 1800s. Logging was arguably the most damaging practice to our local watersheds. To transport logs, pole roads were constructed in local streams. This technique caused massive erosion in the streams which caused landslides in some areas.

Watershed Threats in the Present
The CWC identifies “areas of concern” each year when we do Snapshot Day. Areas of Concern are water bodies that are monitored and found to exceed the objectives for three parameters or more. There is more information about these in the Water Quality Parameter section. In 2006, there were 26 areas of concern on ten waterbodies. Waterbodies throughout the lower Salinas watershed north to the Watsonville Slough continue to have high nutrient, turbidity and E. coli concentrations. Two of the biggest sources of pollution is urban runoff and agricultural runoff.

Urban Runoff
Urban Runoff or ‘storm drain pollution’ is one of the leading causes of water pollution in this country. Urban areas contain up to 90 percent hard surfaces such as rooftops and pavement where water collects and quickly runs off. Urban Runoff is difficult to prevent because it is nonpoint pollution. That is, instead of originating from a single-point source, such as a factory or sewage treatment plant, the sources of urban runoff are spread throughout an urban area. Such sources include yards, sidewalks, streets, construction sites and parking lots. Any deposits of oil, grease, pesticides, herbicides, soil, pet droppings, etc. in these areas are flushed by rainwater and other means down the storm drains and directly into a river or bay (Source: Monterey National Marine Sanctuary). The EPA estimates that 70% of water pollution comes from stormwater and sewer discharge. This increase in flow can have impacts on sediment, riparian plant life, and erosion.

Agricultural Runoff
In the Monterey Bay Area there is extensive agriculture. Overgrazing and un-sustainable agricultural practices can lead to significant sediment washing into our local creeks and streams. Agriculture also uses a lot of chemicals and pesticides that can get into out water. Common substances that farms use on crops are phosphorous, nitrogen plastic, and various insecticides, herbicides, and fungicides. Badly managed manure and animal feed can lead to bacteria and pathogens getting into the water.

Focus on the Pajaro River
The Pajaro River forms the base of one of the largest watersheds on the Central Coast, compromising over 1,300 miles. The natural geology of the area surrounding the river is termed as overfit which means that the channel is smaller than the river. This makes the river naturally inclined to flood. Humans have impacted the river by reducing the amount of Riparian plants which has lead to heavy erosion on the banks. Erosion has made the river even more likely to flood. The Army Corp of Engineers has been using levees to control these floods since the 1940s. In 1995, after especially damaging floods, much of the remaining Riparian Forest was removed in an effort to reduce flooding. This has actually made the flooding worse. The Corp has proposed to rebuild the existing levee system which has become a very controversial proposal. Many groups want the Corp to address the degradation of the river and loss of Riparian life instead of continuing with the levee system. The river is also the most polluted of the rivers that go into Monterey Bay National Marine Sanctuary. For these reasons, the America’s River organization has named the Pajaro River as the number one most endangered river in 2006. (Source: America’s Rivers).