The Tahoe Region contains 63 streams that flow into Lake Tahoe. Streams account for a portion of the nutrients and sediments going into Lake Tahoe, and play a large role in Lake Tahoe's clarity. Policy and management actions to attain standards for Tahoe Region tributary waters are implemented through the TRPA Regional Plan and the Environmental Improvement Program, and generally aim to reduce pollutant loading to Lake Tahoe. These actions include projects to restore stream environment zones (SEZ) and limit the rate and extent of urban growth. The Lake Tahoe Interagency Monitoring Program routinely monitors seven streams to track water quality conditions and pollutant levels in the streams.