26.17.07.03

.03 Conditions and Procedures.

A. Subject to the Department's approval, provision of low flow augmentation by the permittee may occur at any location within the Potomac River Basin above Great Falls regardless of the location of the consumptive use. The Department may require the permittee situated on a tributary of the Potomac River to locate the low flow augmentation facility upstream from the point of withdrawal if deemed necessary for the environmental protection of instream values.

B. The amount of required low flow augmentation shall be calculated for the location at which the withdrawal occurs or, if the consumptive use occurs on a tributary and augmentation is provided on the Potomac River, at the confluence of the tributary and the Potomac River.

C. The total amount of low flow augmentation storage, in billions of gallons, required of a permittee by the Department shall be interpolated from the following table:

Time of travel in days from the storage facility to the Washington Metropolitan Area at Great Falls

0 1 2 3 4 5
1 .089 .124 .124 .124 .124 .124
Consumptive 10 .9 1.2 1.3 1.3 1.3 1.3
use of 20 1.8 2.4 2.7 2.7 2.7 2.7
permittee 30 2.8 3.6 4.0 4.0 4.1 4.1
in millions 40 3.8 4.7 5.3 5.3 5.4 5.4
of gallons 50 4.9 6.1 6.7 6.7 6.7 6.7
per days 60 6.0 7.2 8.1 8.1 8.1 8.1
70 7.0 8.6 9.5 9.5 9.5 9.5
80 8.3 9.8 10.9 10.9 10.9 12.0
90 9.4 11.3 12.4 12.4 12.6 12.6

D. The Department shall direct the permittee as to when and for what duration consumptive water use must cease or a release from a water storage facility must be made for low flow augmentation for consumptive water use.

E. Total nonexempt consumptive use on a daily basis by a permittee may not exceed the value used in calculating water augmentation requirements during low flow restriction periods.

F. If the permittee elects to construct the low flow augmentation storage facility in Virginia, West Virginia or Pennsylvania, the permittee shall secure the necessary agreements with the appropriate jurisdiction to enable the permittee to operate the augmentation facility in compliance with this regulation.

G. Municipal residential water use permittees, upstream from the Washington metropolitan area, when notified by the Department that the water use restriction stage had been declared in the Washington metropolitan area, shall reduce all withdrawals from the Potomac River Basin or its tributaries to a level corresponding to the average daily withdrawal by the permittee during the previous January, February, and March.