Texas Administrative Code › Title 30 - ENVIRONMENTAL QUALITY › Part 1 - TEXAS COMMISSION ON ENVIRONMENTAL QUALITY › Chapter 298 - ENVIRONMENTAL FLOW STANDARDS FOR SURFACE WATER › Subchapter E - GUADALUPE, SAN ANTONIO, MISSION, AND ARANSAS RIVERS, AND MISSION, COPANO, ARANSAS, AND SAN ANTONIO BAYS › Section 298.380 - Environmental Flow Standards

Current through Reg. 49, No. 28; July 12, 2024
(a) A
				  water right application in the Guadalupe and San Antonio River Basins and the
				  San Antonio-Nueces Coastal Basin, which increases the amount of water
				  authorized to be stored, taken, or diverted as described in §
										298.10
				  of this title (relating to Applicability), shall not cause or contribute to an
				  impairment of the inflow regimes as described in the figures in this
				  subsection. Impairment of the inflow regime shall be evaluated as part of the
				  water availability determination for a new water right or amendment that is
				  subject to this subchapter. For purposes of this subsection, impairment would
				  occur if the application, when considered in combination with any
				  authorizations subject to this subchapter, which were issued prior to this
				  application, would impair the modeled permitting frequency of any inflow regime
				  by more than the values set out in paragraphs (3)(A) - (C) and (4)(A) - (C) of
				  this subsection.
(1) Impairment to the
				  modeled permitting frequency shall be calculated individually for each inflow
				  regime level in Figure: 30 TAC § 298.380(a)(3) andFigure: 30 TAC §
				  298.380(a)(4) for which a specific frequency is identified at the most
				  downstream point in the water availability model, which represents inflows to
				  San Antonio Bay.
(2) Impairment is
				  calculated by addition or subtraction of the values set out in paragraphs
				  (3)(A) - (C) and (4)(A) - (C) of this subsection, except that impairment of
				  inflow regime Spring 4 and Spring 5 combined shall be calculated as set out in
				  paragraph (3)(C) of this subsection.
(3) Bay and Estuary Freshwater Inflow
				  Standards for the San Antonio Bay System for the Spring Season.
Attached
					 Graphic
(A) The modeled
				  permitting frequencies for inflow regimes Spring 1, Spring 2, and Spring 2 and
				  Spring 3 combined, as described in Figure: 30 TAC § 298.380(a)(3), and
				  calculated as a percentage of total years, shall not be decreased by more than
				  5%.
(B) The modeled permitting
				  frequencies for the inflow regime Spring 6, as described by Figure: 30 TAC
				  § 298.380(a)(3), and calculated as a percentage of total years, shall not
				  be increased by more than 8%.
(C)
				  The modeled permitting frequency for inflow regime Spring 4 and Spring 5
				  combined, as described in Figure: 30 TAC § 298.380(a)(3), and calculated
				  as a percentage of Spring 5 years to the total combined years, shall not be
				  increased to more than 67% of the total years.
(4) Bay and Estuary Freshwater Inflow
				  Standards for the San Antonio Bay System for the Summer Season.
Attached
					 Graphic
(A) The modeled
				  permitting frequencies for inflow regimes Summer 1, Summer 2, and Summer 1 and
				  Summer 2 combined, as described in Figure: 30 TAC § 298.380(a)(4), and
				  calculated as a percentage of total years, shall not be decreased by more than
				  5%.
(B) The modeled permitting
				  frequencies for the inflow regime Summer 7, as described by Figure: 30 TAC
				  § 298.380(a)(4), and calculated as a percentage of total years, shall not
				  be increased by more than 8%.
(C)
				  The modeled permitting frequency for inflow regime Summer 4 and Summer 5
				  combined, as described in Figure: 30 TAC § 298.380(a)(4), and calculated
				  as a percentage of Summer 5 years to total combined years, shall not be
				  increased to more than 10%.
(5) Bay and Estuary Freshwater Inflow
				  Standards for Mission and Aransas Bays for the Summer Season.
Attached
					 Graphic