Texas Administrative Code › Title 30 - ENVIRONMENTAL QUALITY › Part 1 - TEXAS COMMISSION ON ENVIRONMENTAL QUALITY › Chapter 298 - ENVIRONMENTAL FLOW STANDARDS FOR SURFACE WATER › Subchapter C - SABINE AND NECHES RIVERS, AND SABINE LAKE BAY › Section 298.275 - Schedule of Flow Quantities

Current through Reg. 49, No. 28; July 12, 2024
(a)
				  The environmental flow standards adopted by this subchapter constitute a
				  schedule of flow quantities made up of subsistence flow, base flow, and one
				  level of high flow pulses. Environmental flow standards are established for ten
				  measurement points in §
										298.280
				  of this title (relating to Environmental Flow Standards) and this
				  section.
(b) Subsistence flow. The
				  applicable subsistence flow standard varies depending on the seasons as
				  described in §
										298.255 of
				  this title (relating to Definitions). For a water right holder to which an
				  environmental flow standard applies, at a measurement point that applies to the
				  water right, the water right holder may not store or divert water, unless the
				  flow at the measurement point is above the applicable subsistence flow standard
				  for that point. If the flow at the measurement point is above the subsistence
				  flow standard but below the applicable base flow standard, then the water right
				  holder may divert or store water according to its permit, subject to senior and
				  superior water rights, as long as the flow at the measurement point does not
				  fall below the applicable subsistence flow standard.
(c) Base flow. The applicable base flow level
				  varies depending on the seasons as described in §
										298.255 of
				  this title. For a water right holder to which an environmental flow standard
				  applies, at a measurement point that applies to the water right, the water
				  right holder is subject to a base flow standard. For a water right holder to
				  which an environmental flow standard applies, at a measurement point that
				  applies to the water right, when the flow at the measurement point is above the
				  applicable base flow standard, but below any applicable high flow pulse trigger
				  levels, the water right holder may store or divert water according to its
				  permit, subject to senior and superior water rights, as long as the flow at the
				  measurement point does not fall below the applicable base flow
				  standard.
(d) High flow pulses.
				  High flow pulses are relatively short-duration, high flows within the
				  watercourse that occur during or immediately following a storm event. They
				  flush fine sediment deposits and waste products, restore normal water quality
				  following prolonged low flows, and provide longitudinal connectivity for
				  species movement along the river.
(1) Two
				  pulses per season are to be passed during the Spring and Fall seasons and one
				  pulse per season is to be passed during the Winter and Summer seasons (i.e., no
				  storage or diversion by an applicable water right holder), if the flows are
				  above the applicable base flow standard, and if the applicable high flow pulse
				  trigger level is met at the measurement point. The water right holder shall not
				  divert or store water except during times that streamflow at the applicable
				  measurement point exceeds the applicable high flow pulse trigger level and
				  until either the applicable volume amount has passed the measurement point, or
				  the duration time has passed since the high flow pulse trigger level
				  occurred.
(2) If the applicable
				  high flow pulse flow trigger level does not occur in a season, then the water
				  right holder need not stop storing or diverting to produce a high flow pulse.
				  The water right holder is not required to release water lawfully stored to
				  produce a high flow pulse.
(3) Each
				  season is independent of the preceding and subsequent seasons with respect to
				  high flow pulse frequency.