Total Maximum Daily Load for Altamont New Reservoir
In addition, averaging of a normal and dry year is assumed to be conservative and part
of the implicit MOS.
Due to uncertainty with nutrient model inputs as explained in Section 7.3, an explicit
MOS of 5 percent is also recommended. Due to unknowns regarding estimated versus
actual measurements of loadings to the lake, an explicit MOS is included. The
5 percent MOS is appropriate based upon the generally good agreement between the
GWLF loading model and observed flows, and in the BATHTUB water quality model
and observed values in Altamont New Reservoir (Section 7.3). Since these models
reasonably reflect the conditions in the watershed, a 5 percent MOS is considered to be
adequate to address the uncertainty in the TMDL, based upon the data available. The
MOS can be reviewed in the future as new data is developed.
8.3.4 Waste Load Allocation
There are no point sources in the watershed; therefore, no WLA (WLA = 0 pounds) is
recommended at this time.
8.3.5 Load Allocation and TMDL Summary
Table 8-3 shows a summary of the TMDL for Altamont New Reservoir. On average, a
total reduction of 84 percent of total phosphorus loads to Altamont New Reservoir
would result in compliance with the water quality standard of 0.05 mg/L total
Table 8-3 TMDL Summary for Total Phosphorus in Altamont New Reservoir
537 0 510 27 2,654 84%
Table 8-4 shows the respective reductions needed from internal cycling, atmospheric
loads, and nonpoint sources in the watershed to meet the TMDL. The reduction of
atmospheric loads is zero because atmospheric contributions cannot be controlled by
watershed management measures. The percent reduction from internal cycling is
estimated as 90 percent based on attainable reductions from management measures that
will be discussed in Section 9. An approximate 74 percent reduction of nonpoint
sources from the watershed, in addition to the reduction of internal cycling, would be
necessary to meet the load allocation presented in Table 8-3. Methods to meet these
targets will be outlined in Section 9.
Table 8-4 Sources for Total Phosphorus Reductions
(lb/yr) Percent Reduction
Atmospheric 15 0 0
Internal Cycling 2,047 1,842 90%
Nonpoint Sources 1,103 812 74%
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