model to the Hanford system i s given. Some d e t a i l s o f the chemical submodel are discussed in the appendix.

This report documents the results of two Hanford groundwater scenario .* studies. The first study examines the hydrologic impact of increased 3 groundwater recharge resulting from agricultural development in the Cold Creek Valley located west of the Hanford Reservation. The second study involves recovering liquid radioactive waste which has leaked into the groundwater flow system from a hypothetical buried tank containing highlevel ,radioactive waste. The predictive and control capacity of the onsite Hanford modeling technology is used to evaluate both scenarios. The results of the first study indicate that Cold Creek Valley irrigation is unlikely to cause significant changes in the water table underlying the high-level waste areas or in the movement of radionuclides already in the ground water. The hypothetical tank leak study showed that an active response (in this case waste recovery) can be modeled and is a possible alternative to passive monitoring of radionuclide movement in the unlikely event that high-level waste is introduced into the ground water. iii ARH-SA-292

Water and L a n d R e s o u r c e s D e p a r t m e n t T h i s r e p o r t i s based on w o r k sponsored by t h e A t l a n t i c R i c h f i e l d H a n f o r d C o m p a n y under U n i t e d S t a t e s A t o m i c E n e r g y C o m m i s s i o n C o n t r a c t A T ( 4 5 -1 ) -2 1 3 0 BATTELLE P A C I F I C NORTHWEST LABORATORIES RICHLAND, WASHINGTON 9 9 3 5 2

S . W. A h l s t r o mR. G. B a c a W a t e r and L a n d R e s o u r c e s D e p a r t m e n t T h i s r e p o r t i s based on w o r k sponsored by t h e A t l a n t i c R i c h f i e l d H a n f o r d C o m p a n y under U n i t e d S t a t e s A t o m i c E n e r g y C o m m i s s i o n C o n t r a c t A T ( 4 5 -1 ) -2 1 3 0