San Diego’s Watershed and and Examination of Land Cover in Relation to Pollution

Tamera Ashcraft

30 November 2000

Outline

Background on the San Diego River, Mission Bay and San Diego Bay

Contamination and Habitat Destruction in the Bays

The San Diego Watershed

Urbanization of San Diego

Summary

San Diego River History

The San Diego River originally flowed into San Diego Bay

Attempt to divert it in 1853 by the Army Corps of Engineers – failed

Another attempt in 1875 – successful

SD river drains 440 sq. miles

San Diego History

1870’s - San Diego population was 2300Population in 1900 was 18,000The population doubled from 250,000 in 1940 to 500,000 in 1948 Sea World built

In 1940 plan to fill in the marshes on the south side of Mission Bay to make an airport

Mission BayMission Bay drains approx 53 sq. miles

Mission Bay water quality problems from bacterial contamination and from urban runoff

High nutrient load

High heavy metal content

Implementing plans to limit non-point source pollution

San Diego Bay

415 sq. miles watershed drainage

SD Bay has been contaminated by the power plant cooling, dammed tributaries, urban runoff, heavy metals from ships, and from a salt production plant

Area of Study

An area of Southern CaliforniaAn area of increasing population growthAn area where rare habitats –Salt Marsh and Torrey Pines - are being threatened by urbanization and dredging

#Sa n D ie goSa n D ie goSa n D ie go

San Diego River

This is the San Diego area

Highlighted is the San Diego River

It flows through a reservoir, a dam, and finally into Mission Bay

# San DiegoSan DiegoSan Diego

San Diego Watershed

¼ of the San Diego River watershed is used for urban or agricultural purposesThe San Diego River deposits bacteria- and nutrient-rich water into the Bay

# San DiegoSan DiegoSan Diego

Urban San Diego County

This is the portion of San Diego County that is UrbanThe salt marsh habitats have been nearly eliminatedSalt marsh is important for cleansing the water and as habitat for marine invertebrates and juvenile fishSan Diego Bay and Mission Bay have been damaged by dredging and habitat destruction

# San DiegoSan DiegoSan Diego

Land Use/Land Cover

This is Land Use/ Land Cover Data for the San Diego Bay and Mission Bay areas

The Urban area is highlighted in blue (all of the area is urban)

Land Use

Bays, lakes, reservoirs

Residential, commercial

Cropland, pasture, orchardUrban

Shrub and Brush Rangeland

Evergreen Forest Land

Transitional Areas, Exposed Rock

Transportation, Community, Utility

Summary

The San Diego River has been diverted from San Diego Bay into Mission BaySan Diego’s population continues to grow – urbanization is rampantThis has resulted in a lot of habitat destructionWhat is the fate of the endangered species that depend on the contaminated water of the San Diego area and the salt marsh which is being destroyed?