INTRODUCTION
The City of Nevada City is located approximately 60 miles northeast of Sacramento, at the junction of State Routes 49 and 20. The City is surrounded by heavily forested lands and is roughly 2,500 feet in elevation. The historical downtown and recreational opportunities in the area have made Nevada City an important tourist destination. As the Nevada County seat, it is also home to governmental offices, as well as the headquarters for the Tahoe National Forest, several schools, and the Nevada City Tech Center employment hub. The day-time population increases by 50 to 70 percent as a result of this workforce. It also increases regularly on weekends, holidays and over the summer months with considerable influxes of tourists. The City covers approximately two square miles, of which 60 percent is served with treated water. There are approximately 1,350 water customers located within the city limits.
Water Infrastructure History
Nevada City was settled in 1849 and almost immediately began development of a gravity-pressure water system. This gravity-flow water system served the dual purpose of providing fire-fighting flows, as well as water to supply hydraulic mining. An extensive network of canals and conduits was built to convey water within the City and to surrounding areas. A catastrophic fire in 1856 resulted in the installation of pressure pipes to increase fire protection capabilities in the downtown area. Much of the infrastructure in the City dates from this early installation and, while segments of the system have been replaced over time, much of the downtown is served by pipes and mains that date from the 1860s and ‘70s.
Nevada City’s canals and conduits have been operated by a variety of water companies over the years (e.g., South Yuba Canal Company, Excelsior Ditch Company). The system was eventually consolidated and is now owned or managed by either PG&E or the Nevada Irrigation District (NID). The City has pre-1914 water rights to Little Deer Creek an intermittent stream that is typically dry from mid-July through mid-November. Since the late 19th century, the City has purchased supplemental untreated raw water from NID. Today, the NID service area completely surrounds the City, currently providing raw water to the City and the City’s water treatment plant (installed in the 1970s). Additionally, NID treats water for distribution to City residents. The City currently utilizes 300,000 to 400,000 gallons per day (gpd) of water in the winter months and experiences a peak summer use of 1.4 million gpd (mgd).
The Problem
The infrastructure that distributes treated water varies considerably in age and condition, with some portions of the system in excess of 100 years old. While small improvements and expansions have been made over time, much of Nevada City’s system is old, inefficient, degraded and in immediate need of upgrade and repair. The overall purposes of this project are to: accomplish the highest priority system improvements, assist the City in preparing and implementing long-term system and customer conservation, and enable the City to engage in water shortage contingency planning.
The Projects
The Nevada City project package includes eight projects:
# 1 – Gracie Road Intertie
# 2 – South Pine Street Distribution System Improvement
# 3 – Park Avenue Distribution System Improvement
# 4 – Prospect Street Distribution System Improvement
# 5 – Install Altitude Valves With Integrated SCADA Systems
# 6 – Leak Detection Program