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<br />P values < alpha)/lOO where alpha is the
<br />specified significance level.
<br />Estimated project duration values
<br />suggest that the Moroccan program must
<br />operate efficiently at least 6 years with 10%
<br />increases for at least a 50% probability-of-
<br />detection (alpha = 0.1). However. if the cloud
<br />seeding program achieves a 15% increase in
<br />seasonal streamflow, at least a 75% probability
<br />of detection can be achieved with a 6-year
<br />treated period and alpha is set at the more
<br />stringent 0.05 level.
<br />
<br />5. HYDROLOGIC AND ECONOMIC
<br />BENEFIT - COST STUDY
<br />
<br />The hydrologic and economic study was
<br />designed to evaluate the distribution and use
<br />patterns of added streamflow that might be
<br />produced by cloud seeding operations in the
<br />Oued Oum er Rbia Basin and then provide a
<br />benefit - cost analysis of the value of the
<br />additional streamflow produced versus the total
<br />cost of cloud seeding operations (Cheney and
<br />Shuyler, 1987). Cheney and Shuyler used a
<br />river simulation model from the Government of
<br />Morocco to determine the physical impact of
<br />5 and 10% increases in streamflow from 1939
<br />to 1984. The results were combined with
<br />economic values of additional water for
<br />irrigation, domestic and industrial purposes,
<br />and hydroelectric power to determine the
<br />benefit to cost ratio for the project.
<br />Preliminary analysis indicates a benefit to cost
<br />ratio of 1.2 and 2.2 for 5 and 10% increases,
<br />respectively. The internal rate of return was
<br />estimated at 23 and 70% for 5 and 10%
<br />increases, respectively.
<br />
<br />6. SUMMARY AND CONCLUSIONS
<br />
<br />The Programme AI Ghait - Winter
<br />Snowpack Augmentation Demonstration
<br />Project in Morocco's High Atlas Mountains has
<br />conducted scientific seeding operations using
<br />target-control nonrandomized statistical design
<br />since 1984. Operational cloud seeding
<br />efficiency levels were 10 to 15% during the
<br />project's first field season in 1984 and increased
<br />to 40 to 70% only after ground generators were
<br />installed in January 1987. The efficiency
<br />increased to 70 to 80% in 1988 as operators
<br />gained experience and communications
<br />improved. The preliminary physical analyses of
<br />clouds are encouraging and indicate that
<br />seedable clouds often occur. At least 6 years
<br />of efficient cloud seeding operations producing
<br />a 10 to 15% increase in streamflow must be
<br />conducted to achieve acceptable probability-of-
<br />detection levels. Given that efficient cloud
<br />
<br />seeding operations did not begin until February
<br />1987 after the ground-based generators were
<br />installed, the project should continue
<br />operations through the 1992-93 winter season.
<br />The preliminary estimates from the
<br />hydrologic-economic analyses are encouraging.
<br />However. evaluation of actual streamflow
<br />observations is needed to properly assess the
<br />physical meaning of these economic estimates.
<br />USAID assistance on Programme AI
<br />Ghait is scheduled to end during 1989. A final
<br />r,eport from USBR to USAID containing more
<br />details on this project should be available by
<br />tlh~ end of the year.
<br />
<br />REFERENCES
<br />
<br />Baddour, 0., and R. Rasmussen, 1988:
<br />Microphysical observations over the Atlas Mountains in
<br />Morocco. Pre print, 10th International Cloud Physics
<br />Conference, WMO, pp. 356-358.
<br />Baddour, 0., M. Nbou, M. EI Mokhtari, R. M.
<br />Rasmussen, D. B. Johnson, and D. A. Matthews, 1989:
<br />S,eedability of Moroccan Clouds. 5th International
<br />Weather Modification and Applied Cloud Physics
<br />Conference, WMO.
<br />Benassi, M., 1988: Adaptation of the SCPP
<br />targeting model to Morocco. Unpublished; available from:
<br />Direction de la Meteorologie Nationale, DDR-Mcteo,
<br />Aeroport Casa-Anfa, BP 8106, Casablanca 02, Morocco.
<br />Cheney, R. W.. and K. D. Shuyler, 1988: Work plan
<br />for hydrologic and economic em/l/ations within Programme
<br />Al Ghait. Bureau of Reclamation, Denver, CO, 18 pp.
<br />EI Majdoub, A, J. G. Medina, and H. R. Orville,
<br />1989: Adaptation of the Rhea orographic precipitation
<br />model to Morocco. 5th International Weather
<br />Modification and Applied Cloud Physics Conference,
<br />WMO.
<br />Hartzell, C., D. Matthews, B. Silverman,
<br />S. Benarafa, M. Maidane, A. EI Majdoub, Y. LeGoff,
<br />1986: Operations plan, Programme Al Ghait. Bureau of
<br />Reclamation, Denver, CO, 200 pp.
<br />Loukah, EI B., 1986: Preliminary Studies of Cloud
<br />Seedabilitv over the Atlas Mountains. M.S. Thesis, Soulh
<br />Dakota School of Mines and Technology, Rapid City, SO,
<br />80 pp.
<br />Mielke, P. W.. Jr., K. J. Berry, and J. G. Medina,
<br />1982: Climax I and II: distortion resistant residual
<br />analyses. J. Appl. Meteor., 21, 788-792.
<br />Mielke, P. W.. Jr., and J. G. Medina, 1987: A design
<br />for evaluation of cloud seeding effects on streamflow in
<br />Morocco. Bureau of Reclamation, Denver, CO, 46 pp.
<br />Rauber, R. M., R. D. Elliott, and A. W. Huggins,
<br />1987: The SCPP targeting model, Final repon for the SCPP
<br />meteorological aJld statistical suppon. Electronic
<br />Techniques. Inc., Fort Collins, CO, pp. 173-222.
<br />Rhea, J. 0., 1978: Orographic precipitation model
<br />for hydrometeorological use. Atmospheric Science Paper
<br />No. 12,7, Colorado State University, Fort Collins, CO,
<br />198 pp.
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