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cussed, a direct drainage area to flow ratio is not typically valid because it does not consider drainage basin character- istics, soil types, antecedent moisture condition, vegetative cover, or other factors that are usualiy considered in a hydro- logic analysis, and 2) the runoff used in calculating the Bolton Draw yield also did not reflect the aforementioned consider- ations, and the instantaneous direct runoff of 8 inches seems unreasonable given that the entire annual average precipitation is only 11 inches. In Addendum II, page 4, the applicant acknow- ledges that their estimate is high but did not attempt to revise it since limited data was available. As the mean annual water yield is not the deciding factor in AVF determinations for either North Fork or Bolton Draw, it is not necessary that the applicant recalculate the mean annual yields at this time in order to make those determinations. However, it is necessary that the appli- cant recalculate the mean annual yield from Bolton Draw and/or S coordinate monitoring activities with the Marr Strip mine for ~b that purpose in order to allow an evaluation of the cumulative ~ impacts of mining to surface water quantity in Bolton Draw. Therefore, the following stipulation is proposed. ,~ Y ~J,, The applicant shall recalculate the mean annual yield from ~`1 Bolton Draw and/or coordinate monitoring activities with the Marr Strip Mine for that purpose. The applicant should ~~ consult the regulatory authority for guidance in choosing an ~ appropriate means of deriving the mean annual flow. ~,~ ~ Consultation shall occur within sixty days after the permit '' is issued. The new data should also be accompanied by a \~ ~ re-evaluation of potential impacts to flow in Bolton Draw. North Fork of Bolton Draw Below the Permit Area Well 2, the sole alluvial monitoring well, has been installed along North Fork immediately downstream of the permit area in a unit of alluvium which is an extension of the unconsolidated deposits lining the main Bolton Draw stream -86-