Recommended Sampling Locations

for

Process Control Monitoring

 

Table 1 provides recommended locations for process control monitoring.  An illustration of the raw water supply system is presented at the bottom of this page.  Sampling frequency should be monthly in the reservoirs, except August - October where sampling twice per month is recommended.  Sampling along the rivers below the terminal reservoirs, canals, and WTPs should be conducted every 7-10 days.  Temperature and T&O compounds (MIB, Geosmin, cyclocitrol) are the most important to measure, with chlorophyll-a, planktonic algae counts, dissolved organic carbon, and nutrients also very useful in the reservoirs.

 

Table 1 – Location and Justification of monitoring sites.  Sampling will be conducted by Central Arizona Project (CAP), Salt River Project (SRP), and Arizona State University (ASU)

 

Monitoring Site

Rationale

Terminal Lakes

 Lake Havasu (CAP samples)

 Lake Pleasant (SRP samples)

 Lake Bartlett (SRP samples)

 Lake Saguaro (SRP samples)

Algae growth in the lakes is a primary source of T&O entering WTPs; monitoring reservoirs also prediction of the duration of T&O occurrence, allowing utilities to order PAC supplies, etc.

Rivers

 Verde River at Beeline Hwy

 Salt River at Bluepoint Bridge

These sites are downstream of terminal lakes and represent influent water to the SRP canal system; storm runoff affects T&O in rivers

CAP Canal

  Above Aqua Fria Siphon

  Wadell Canal

  Above SRP cross-connect

CAP canal provides water to Union Hills WTP and to the head of the SRP canals; historically T&O levels are lower in CAP water than SRP water and offer opportunities to blend sources to control T&O

Arizona Canal

 Above/blw CAP cross-connect

 At Beeline Highway

 Pima Road

 56th Street

 Central Street

For the past 3 years three different “hot spots” for T&O production have been identified. Frequent monitoring has localized “hot spots” and allowed for copper treatment or canal brushing by SRP to reduce in-canal T&O production

South Canal

  Below CAP cross-connect

  Head of Consolidated and Tempe Canal

Quantifies potential production in the South canal and provides baseline for Cities of Chandler (Consolidated Canal) and Tempe (Tempe Canal)

Water Treatment Plants

 (Influent and Effluent samples)

  Union Hills (CAP canal)

  Squaw Peak (AZ canal@ 24th St)

  Deer Valley (AZ canal@ 24th Ave)

  Val Vista (South Canal)

  Additional City WTPs

Influent T&O concentrations allow optimization of treatment conditions (e.g., PAC type and doses); finished water is quality perceived by customers