Sec. 26.08.03.05. Cooling Water Intake Structures

A. The location, design, construction, and capacity of cooling water intake structures shall reflect the best technology available (BTA) for minimizing adverse environmental impact.

B. The determination of BTA for minimizing adverse environmental impact shall consider the effect of:

(1) Impingement loss as determined in §D of this regulation; and

(2) Entrainment loss as determined in §E of this regulation.

C. Unless otherwise directed by the Department, cooling water intake structures withdrawing less than 10,000,000 gallons per day from surface waters are excluded from the requirements of this regulation if the volume of water is less than 20 percent of the:

(1) Design stream flow for nontidal waters; or

(2) Annual average net flow past the point of discharge which is available for dilution for tidal waters.

D. Determination of Impingement Loss.

(1) The value of the impingement species destroyed by the intake structure shall be determined by estimating the number of each species destroyed and multiplying by the values listed in COMAR 08.02.09.01. These factors shall be weighted by multiplying by the following adjustment factor:

Species Function Factor

(a) Recreational only ---------------------------------- 1.0;

(b) Commercial and recreational ------------------------ 1.0;

(c) Commercial only ------------------------------------ 1.0;

(d) Commercial, recreational, and forage --------------- 0.8;

(e) Commercial and forage ------------------------------ 0.75;

(f) Recreational and forage ---------------------------- 0.75;

(g) Forage --------------------------------------------- 0.75.

(2) Dischargers shall install and operate functional modifications to mitigate impingement loss, provided that the additional cost of installation of modifications to intake structures and of operation modifications over a 5-year period does not exceed 5 times the estimated annual value of impingement loss. These approved modifications shall be defined as BTA under §B(1) of this regulation.

E. Determination of Entrainment Loss.

(1) Definition. For purposes of this regulation only, "significant" means having a statistically measurable effect beyond the mixing zone.

(2) The discharger shall determine the extent of cooling water entrainment loss on a spawning or nursery area of consequence for RIS as defined in Regulation .04 of this chapter.

(3) If entrainment loss results in significant adverse environmental impact, the discharger shall install and operate functional modifications to mitigate entrainment loss. These approved modifications shall be defined as BTA under §B(2) of this regulation.