Illegal dumping of oil and other chemicals is another problem related to urban development. By some estimates, half of the used motor oil from households is dumped illegally on the ground, in storm drains or in landfills where, over time, it may find its way into the Estuary. Erosion Land disturbance associated with construction grading for site preparation and poor farming practices accelerates soil erosion, which leads to increased levels of suspended sediments in surface water. Influences on Land Use Private Sector Decisions For real estate developers, businesses, industry and land owners, economic factors take precedence over growth management and environmental considerations. Locations meeting these criteria are often outside existing cities.
Many land owners follow market conditions in deciding whether to sell their land for development.
Public Sector Decisions City and county governments guide land development through their General Plans and zoning regulations. Regional, state and federal agencies have less direct control over land use, but prepare plans for and regulate the effects of development on specific resources, such as wetlands and geographic areas like San Francisco Bay. Taxes and Laws Tax policies and laws affect the Estuary's land use patterns. Proposition 13, passed in 1978, greatly reduced local governments' property tax revenue, forcing them to rely more heavily on sales taxes, development fees, redevelopment funding, and land annexation, especially for commercial development. As a result, many local governments favor retail development, which generates sales tax revenues, over housing, which requires additional services.