Water and nutrient transport via groundwater from Ward Valley into Lake Tahoe1

The amount of groundwater transported from the Ward Valley watershed into Lake Tahoe during the 1975 water year was 4.1 × 106 m3. This was 16% of the water volume carried by Ward Creek and 10% of the total precipitation within the watershed during the same period. Of the total nutrient loading of Lake Tahoe from the Ward Valley watershed, groundwater contributed 49% of the total nitrate‐nitrogen and 44% of the total soluble phosphorus loads. Groundwater may be a significant source of water and dissolved nutrients for Lake Tahoe, particularly in the littoral zone.