WSP11975 - Laserfiche WebLink

Home Browse Search

~~1 2o~~ 0,25 ~ 0.32 EXPLANATION I MAY - SEPTEMBER SURFACE 7 MAXIMUM 0.20 75TH PERCENTILE MEDIAN <J) ~ 0.15 25TH PERCENTilE a: 0 MINIMUM :J: 0- '3 NUMBER OF <J) 0 0.10 MEASUREMENTS :J: 0- BOnOM <J) 0.32 MAXIMUM GREATER THAN <t a: ~ I GRAPH SCALE w 7 MAXIMUM f- 0.05 :J Q 75TH PERCENTILE a: w 0- 13 <J) '3 '2 13 '3 '3 MEDIAN ::;: 0 <t 25TH PERCENTILE a: to '"l j MINIMUM :J -' OCTOBER - APRIL NUMBER OF ~ '3 MEASUREMENTS ~ <J)' :J 0.20 a: 0 J: 0- <J) 0.15 0 :J: 0- -' <t f- 0 0.10 f- I 0.05 ~~ c;J~ 1 8~ B B B B 0 3B Be 7B SITES Figure 12. Total phosphorus concentrations in Pueblo Reservoir near the reservoir sur1ace and near the reservoir bottom, 1986 through 1989, 0.007 mg/L. The mean flux rate for the four samples was about 0,44 mglm2/day. Because of the small num- ber of samples collected, the above mean flux rates might not represent the spatial and temporal variation in nutrient flux rates that are expected to occur in the reservoir and, therefore, were not used to estimate annual nutrient-load contributions from the bonom sediments. The samples for these estimates were col- lected in August, September, and October during peri- ods when dissolved-oxygen concentrations were less than 3 mg/L in the hypolimnion. Flux rates are expected to decrease during the well-oxygenated peri- ods and increase during periods of complete and pro- longed anoxia. Therefore. nutrient flux from the bonom sediments .can represent a substantial nutrient source for the reservoir during the summer and fall, especially during anoxic periods in the hypolimnion. Although major nutrients, trace elements, light availability, and temperature are all important growth- regulating variables for phytoplankton in lakes and res- ervoirs, it is widely accepted that the major nutrients. phosphorus and nitrogen. are the most common 32 Phyalcal, Chemical, and Biological Characteristics of Pueblo Resarvolr. Colorado, 1985-419