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, . . 0013B5 the return flows would refill these cones of depression instead of flowing out of the state on the surface or being inefficiently used. ADDITIONAL RECHARGE Present irrigation activities provide a considerable amount of recharge. Planned pumping of this groundwater as has been described would make it available for use at the most desirable times. Additional re- charge during periods of relative water surplus could make more water available from such pumps. 'It would have to be done in areas with low water tables. Another major loss which can potentially be salvaged in part is reservoir evaporation. Losses from shallow reservoirs are great, especially during the sUlllller. Long term storage in these reservoirs should be avoided. This water could be stored in deeper upstream reservoirs and in the groundwater aquifer. Then the shallow reservoirs could be used for off-season storage when necessary and for temporary storage of tributary flood water. Perhaps the greatest potential use of additional recharge is near the Colorado-Kansas state line. Both states are now using water with over 4,000 ppm salt for irrigation, but flood flows of higher quality go through the system to the ocean. More than 25% of the groundwater in the Colorado portion of the Arkansas aquifer is located within eight miles of the state line. This is a constantly overflowing reservoir unless the water table is lowered to permit recharge during times of surplus. Present compact provisions allow Colorado to draw up to 750 cfs and Kansas up to 500 cfs at any time between April 1 and October 31, if more than 20,000 acre-feet is in storage. Neither state gets credit for water left in the reservoir if they don't divert at the same time as the other state. This provision tends to discourage conservation. Whenever the reservoir is empty Colorado irrigators divert the available water under the priority system. Kansas just gets a little return flow. Both states are very short of water during critical periods. Kansas could be provided a smaller, continuous water supply during the irrigation season by pumping from the aquifer. Lowering the water table by this method would permit recharging the higher quality flood waters. This would result in a much more dependable, higher quality water supply for Kansas. Colorado could then have full control of John Martin Reservoir, making it theoretically possible to hold the water in storage and use it whenever it would do the most good.. MANAGEMFNT Recharge is only a part of the very complex water resources system in the Arkansas Valley. No part of this system can be altered without changes in the rest of the system. Recharge can be a useful tool if used in conjunction with other tools. Careful study of the entire system must precede any changes if mistakes are to be avoided. Such study is also necessary because of the legal problems involved which need to be worked out by mutual agreement.