Indicator
Phosphorus Concentration (Tributaries)
Basics
Phosphorus Concentration (Tributaries)
Phosphorus Concentration in Streams
Outcome
Program
Each Unit (number)
WQ16: ADOPTED STANDARDS: TRPA: attain applicable state standards for concentrations of dissolved phosphorus; Nevada: the annual average concentration of total phosphates cannot exceed 0.05 mg/L as phosphorus in Incline Creek (NAC 445A.1636) and Third Creek (NAC 445A.1642); California: The annual average value and the 90th percentile value of total phosphorus cannot exceed 0.015 mg/L in the Upper Truckee River, and Trout, General, Blackwood, and Ward Creeks (LRWQCB, 1995).
The indicator is annual average total phosphorus concentration measured over a water year (October 1 to September 30). Annual average total phosphorus concentration is based on samples collected during each water year from each of the seven monitored streams. The number of individual samples collected at each monitoring station in a given water year varied during the period of record from three to 138. Annual average total phosphorus concentrations are reported in milligrams per liter (mg/L). Although the TRPA standard is for state standards for dissolved phosphorus (i.e., the fraction of total phosphorus that will pass through a 0.45-micron filter), the states do not have standards for dissolved phosphorus. Both California and Nevada have standards for total phosphorus, which is what was used for this evaluation.
This Indicator is reported in the following LT Info areas:
Status

Avereage phosphorous concentrations at Third Creek. Third Creek is the only site monitored that shows a significant trend over time. The other six sites monitored show no signficant trends. 

Name Options
Phosphorus Concentration - Streams
General

Program Lake Tahoe Interagency Monitoring Program Stream Monitoring

Approach

The Lake Tahoe Interagency Monitoring Program (LTIMP) stream monitoring program was first developed in 1979 to assess sediment and nutrient input from tributaries to Lake Tahoe, and to support research that aims to understand the drivers affecting the transparency of Lake Tahoe. The tributary monitoring focuses on both event-based conditions (large runoff events associated with rainfall and snowmelt) and baseline conditions (low inflow during summer when precipitation is negligible). Up to 10 streams have been monitored since the early 1990s; five in California (Upper Truckee River, and Trout, General, Blackwood and Ward Creeks) and five in Nevada (Third, Incline, Glenbrook, Logan House, and Edgewood Creeks). Six of these streams have been monitored since water years 1980 or 1981. In water year 2012 the number of streams routinely monitored was reduced to seven (see map above), and all streams have primary monitoring stations at or near the point of discharge to Lake Tahoe. Sampling pr

Partners

Associated Programs data not provided.