First Regular Session Sixty-eighth General Assembly STATE OF COLORADO INTRODUCED LLS NO. 11-0708.01 Thomas Morris HOUSE BILL 11-1231 HOUSE SPONSORSHIP Fischer, Ryden, Vaad SENATE SPONSORSHIP Brophy, Hodge House Committees Senate Committees Agriculture, Livestock, & Natural Resources A BILL FOR AN ACT Concerning the authorization of a study of the South Platte river alluvial aquifer. Bill Summary (Note: This summary applies to this bill as introduced and does not reflect any amendments that may be subsequently adopted. If this bill passes third reading in the house of introduction, a bill summary that applies to the reengrossed version of this bill will be available at http://www.leg.state.co.us/billsummaries.) The bill directs the Colorado water conservation board to conduct a comprehensive study of the interaction between the South Platte alluvial aquifer and surface streams, including specifically: The number and location of alluvial wells withdrawing groundwater in the South Platte river basin; The number and location of alluvial wells in the basin that are currently curtailed from pumping; The impact of well withdrawals on groundwater levels and surface flows in the basin; Whether the current administrative framework achieves the state's dual goals of protection of senior rights and maximization of the beneficial use of waters of the state; and Whether additional usage of the alluvial aquifers could be permitted in a manner consistent with protecting senior rights. The board is to report the results of the study to the general assembly no later than June 1, 2012. Be it enacted by the General Assembly of the State of Colorado: SECTION 1. 37-60-115, Colorado Revised Statutes, is amended BY THE ADDITION OF A NEW SUBSECTION to read: 37-60-115. Water studies - rules - repeal. (7) South Platte river alluvial aquifer study. (a) Legislative declaration. Preceding the passage of the "Water Rights Determination and Administration Act of 1969", article 92 of this title, referred to in this subsection (7) as the "1969 act", the general assembly commissioned a study of the interaction between the South Platte alluvial aquifer and the surface flows in the South Platte river. The results of this study are contained in a report entitled "Engineering Water Code Studies for the South Platte River (Morton W. Bittinger and Associates and Wright Water Engineers, August, 1968)", also referred to as the "Bittinger study". The general assembly considered the results of the Bittinger study in its passage of the 1969 act. Augmentation plans authorized under the 1969 act are operating on a large scale in the South Platte river basin. Many scientific and technological advances have occurred since the Bittinger study and the passage of the 1969 act, yet no comprehensive study has been conducted since 1968 regarding the impact of alluvial groundwater usage on the South Platte river or the relative success of augmentation plans authorized by the 1969 act in protecting senior surface diverters and maximizing the use of the waters of the state. The general assembly finds that the South Platte alluvial aquifer plays a critical role in the state's economy, that development of this aquifer is and will continue to be an important source of water supply for future development, and that it is appropriate at this time to engage in additional study on these matters. (b) Study authorized. In furtherance of the purposes stated in paragraph (a) of this subsection (7), the board shall, in consultation with the state engineer, commission a comprehensive study of the interaction between the South Platte alluvial aquifer and surface streams. The study shall investigate, without limitation: (I) The number and location of alluvial wells withdrawing groundwater in the basin; (II) The number and location of alluvial wells in the basin that are currently totally or partially curtailed from pumping; (III) The impact of well withdrawals on groundwater levels and surface flows in the basin, including, without limitation, investigation of the following issues: (A) Current and historical groundwater levels; (B) Current and historical amounts of water leaving the state in excess of compact requirements; (C) Current and historical deliveries to senior surface rights; (D) The relationship between groundwater pumping and nonbeneficial consumptive use; (E) The impact of the following on surface flows and groundwater levels: Existing and projected reuse of transbasin and other fully consumable supplies; existing and projected conservation practices; installation of lined storage facilities in the alluvium; and installation and operation of alluvial recharge facilities; (F) The number, size, scope, and effectiveness of augmentation plans operating in the basin and the impact of these plans on the issues specified in this subparagraph (III); (G) Whether and to what extent depletions caused by past pumping of the wells in the basin continue to impact the surface streams, considering current and historical groundwater levels; (IV) Whether the current administrative framework achieves the state's dual goals of protection of senior rights and maximization of the beneficial use of waters of the state; and (V) Whether additional usage of the alluvial aquifers could be permitted in a manner consistent with protecting senior rights. In this regard, the study must include an investigation of the following concepts: (A) Planned use of available groundwater storage to maximize the sustainable yield of the basin, including the potential for additional draws on groundwater during times of drought, followed by intentional recharge activities in times of surplus; (B) Service of senior surface rights by groundwater pumping, either directly or via the use of retiming wells providing surface flow during times of shortage; (C) Whether management based upon measured groundwater levels could increase basin efficiency and protect senior surface rights; (D) Whether it would be beneficial to assign the state engineer increased management responsibility in the basin, and, if so, the nature and extent of this responsibility. In this regard, the study shall consider, without limitation, the impact of current reservoir fill season administrative practices and whether such practices could be improved to allow increased efficiency in a manner consistent with protecting senior rights. (E) Use of the South Platte decision support system as a management and planning tool to more effectively manage the South Platte river system to facilitate conjunctive use of groundwater and surface supplies. To the extent the South Platte decision support system does not currently support this functionality, the study shall investigate the feasibility and cost of making necessary improvements to accomplish this goal. (F) The establishment of a basin-wide network of monitoring wells, a pilot project, or both, in a specific location to verify and calibrate existing groundwater models and methods of calculating the depletive effects of well pumping and the accretive effects of recharge activities in the South Platte river, including those incorporated in the South Platte decision support system. (c) The board shall commence the study as soon as practicable and shall report the results of the study to the general assembly no later than June 1, 2012. SECTION 2. Act subject to petition - effective date. This act shall take effect at 12:01 a.m. on the day following the expiration of the ninety-day period after final adjournment of the general assembly (August 10, 2011, if adjournment sine die is on May 11, 2011); except that, if a referendum petition is filed pursuant to section 1 (3) of article V of the state constitution against this act or an item, section, or part of this act within such period, then the act, item, section, or part shall not take effect unless approved by the people at the general election to be held in November 2012 and shall take effect on the date of the official declaration of the vote thereon by the governor.