Golden Alga (Prymnesium parvum ) Salt River Lakes Marc Dahlberg Water Quality Program Manager March 8, 2011

Golden Alga  Temperature range between 5 and 30 degrees Celsius  Blooms occur when nutrients are readily available.  When nutrients become depleted toxins are released.  The potency of the Golden alga is nearly five times greater at a pH 8.5 than it is at 6.5.  Cells are very fragile and are easily ruptured  Prefers a saline environment – does very well in waters with conductivities over 2000 µmhos/cm

Diagnostic Features  8 – 11 microns long  3 – 6 microns wide  Nucleus is located centrally between two chloroplasts  2 equal flagella and a well developed heptonema

Conductivity Saguaro - Canyon – Apache - Roosevelt

Conductivity Saguaro - Canyon - Apache

Average Conductivity Saguaro - Canyon - Apache

Average Conductivity Salt River Lakes (Saguaro- Canyon-Apache) and Salt River below Saguaro

Conductivity Comparison

Dead or Dry Roosevelt Lake -  1928, 1929, 1930, 1931, 1934, 1938, 1940, 1947, 1950, 1951, 1956 San Carlos Lake –  1934, 1938, 1939, 1940, 1946, 1947, 1948, 1950, 1951, 1952, 1953, 1955, 1956, 1957, 1960, 1961, 1965, 1971, 1976, 1977 Bill Silvey

Average Conductivity Salt River Lakes (Saguaro-Canyon- Apache) and Roosevelt Lake

Roosevelt Lake

Salt River Flows and Conductivity

Tonto Creek Flows and Conductivity

Roosevelt Lake September 15, 2000 Conductivity

Average Annual Flows at Salt River Diversion Dam

Golden Alga Caused Fish Kills in Waters without Forest Fires  Lake  Conductivity  Kearney Lake  Water Ranch  Lake Las Vegas  2500 – 8500  2700 – 2900 

Waters with Forest Fires that Have Not Resulted in a Golden Alga Fish Kill  Lake  Conductivity  Horseshoe  Bartlett  Black Canyon Lake  400 – 750  400 – 700 

July 2002 July 19, 2002 Conductivity 2570 Flow 263 July 31, 2002 Conductivity 753 Flow 900

Questions? September 14, 2011 Conductivity 1814 Flow 288 CFS Roosevelt million AF Apache 1067 Canyon 1045 Saguaro 1062

Salt River Lakes – Drainage Area  Roosevelt – 5830 square miles  Apache – 5842 square miles (12 sq mi)  Canyon – 6101 square miles (259 sq mi)  Saguaro – 6330 square miles (229 sq mi)  92% of the watershed lies above Roosevelt dam

Salt River Lakes - Storage  Roosevelt – 1,653,043 acre feet (81%)  Apache – 245,138 acre feet (12%)  Canyon Lake – 57,832 acre feet (3%)  Saguaro – 73,613 acre feet (4%)  Total – 2,029,646 acre feet

Conductivity  The specific conductance test measures the ability of water to pass an electrical current. Conductivity in water is affected by the presence of inorganic dissolved solids such as chloride, sulfate, sodium, calcium and others. The greater the concentrations of ions, the larger the conductivity.

Salt River Below Saguaro Lake