Motivation. In the past few decades, water has become the all-important natural resource. While the world population continues to increase with no apparent end in sight, people are seen to be moving, in ever greater numbers, to the drier side of the climatic spectrum. All the while, global climate change is increasingly being tied to the recurrency and severity of floods and droughts, affecting greater numbers of people, across geographical boundaries. Established practices of water engineering, which originated in earnest around the turn of the 20th century, are clearly no longer adequate. There is an urgent need to examine these practices, to confront them with the new reality, and to formulate more imaginative ways of dealing with water, not only as a resource, but also as a critical component of Nature. Only then will we be on the right track toward the much heralded, yet by most account still elusive, goal of achieving sustainability. The questions that follow are a modest contribution to this end.


  1. For each basin, what percentage of precipitation, considering the local and regional climate, can be sustainably used, consumptively or not, by society?

  2. Is it feasible to manage the hydrologic cycle to increase runoff at the expense of ecosystem evapotranspiration?

  3. To what extent it is feasible to manage the hydrologic cycle to increase anthropogenic (artificial) evapotranspiration at the expense of runoff?

  4. Is the technology of artificial production of rainfall (cloud seeding) reliable enough to be widely applied?

  5. How can rainfall harvesting be better implemented to alleviate local water-supply shortages, especially in arid regions?


  6. Is it raining more? Or, is it raining less? Where and why?

  7. In view of anthropogenic climate change, are patterns of rainfall likely to change in the near future?

  8. Is global climate change likely to exacerbate floods and droughts?

  9. In view of global climate change, has the climatological and hydrological record of the past one-hundred years or more now lost its pristine character?


  10. In view of the need to strive for long-term sustainability in water resources development, should the perceived societal strategy of "water to follow the people" be eventually replaced by a strategy of "people to follow the water"?

  11. Does classical human development, which converts forests to range, agriculture, and urban, decrease the availability of water across the climatic spectrum? If so, how can this effect be mitigated locally and regionally?

  12. Should interbasin water transfers be pursued or discouraged in future water resources development?

  13. In a situation of water scarcity, which is very likely to be exacerbated in the years to come due to the population explosion, what priorities, if any, should be used in allocating water to the various sectors of society (animal husbandry, agriculture, industrial, urban)?


  14. What steps should be taken to improve the analysis of water balance to better account for the interaction between surface and groundwater?

  15. Is groundwater a commons? If so, should this be legally be established across the land?

  16. Should groundwater be managed at the basin scale? If so, at what scale?

  17. What advantages and disadvantages follow from the use of groundwater on a massive scale? How can the disadvantages be ameliorated?

  18. What principle(s) should govern the sustainable use of groundwater?

  19. Should the focus of groundwater management be shifted from safe yield to baseflow conservation?

  20. Is groundwater sustainability a hydrogeologic problem, or a socio-economic problem?

  21. Is groundwater sustainability an interdisciplinary subject and, therefore, likely to transcend the discipline of hydrogeology?

  22. To what extent should fossil groundwaters be used for development?

  23. Should the use of fossil groundwaters be regulated?

  24. Is isotope hydrology a reliable indication of the age, source and fate of groundwaters?


  25. Should river floods be managed with levees, upstream storage, flood proofing, or a suitable combination of these?

  26. Should flood proofing be more widely used as an effective way to mitigate flood damage?

  27. Is the 100-yr design flood adequate as the only metric for regulation of floodplain use?

  28. Should the 100-yr design flood be applicable across the climatic spectrum, from superarid to superhumid, regardless of geomorphological setting?


  29. To what extent are droughts predictable?

  30. Should drought prediction be an integral part of management?

  31. In drought-prone regions, should societies establish numerical levels of perceived risk (say, 1 to 5), commensurate with the vagaries of the weather?


  32. Should mildly saline surface and groundwaters intended to be used for domestic consumption be treated in order to minimize the long-term risks to public health?


  33. Are sediments good or bad? How should sediments be managed to ensure that they remain a valuable resource?

  34. Should dams be occasionally operated to flush the sediments deposited in downstream reaches, to provide flood control and to enhance ecosystem management?

  35. How should sediment exclusion and/or removal from dams be effectively managed?

  36. How will dam removal affect the local water resources supply?

  37. Should dams be operated for sand mining?

  38. Should sand mining in rivers be regulated to reduce the risk of structural collapse of neighboring bridges?


  39. How should salts be managed at the basin level to ensure that naturally exorheic basins remain exorheic, despite anthropogenic intervention?

  40. Must exorheic basins maintain a minimum amount of runoff to ensure that all salts, natural and anthropogenic, are delivered to the oceans?

  41. In view of the pervasive menace of salinity in arid and semiarid regions, is irrigated agriculture sustainable in the long run?

  42. Should anthropogenic salinity be managed for direct export to the ocean, or for retention and storage in evaporation ponds?

  43. Are brine lines the solution to municipal water supply and irrigation development near coastal areas, in the presence of anthropogenic salinity?

  44. Given that salinity concentration typically increases with groundwater depth, should there be a depth limit imposed on groundwater pumping to avoid bringing additional salts to the surface, where they would be difficult and costly to dispose of?

  45. In view of the increasing use of groundwater to satisfy various needs, should its salinity variation/increase with depth be better documented?


  46. At the basin scale, what percentage of runoff should be reserved by regulation to preserve the biodiversity of all ecoystems, to include lentic, lotic, riparian, transitional, and upland?


  47. Are graduate students in water resources engineering being properly exposed to the interdisciplinary nature of water?

  48. In view of the changing nature of water and climate, does the current graduate curricula adequately reflect the newer challenges?

  49. Do graduate programs in water resources engineering place adequate emphasis on the discipline of geomorphology, which plays a significant role in conditioning rainfall, runoff and streamflow?

  50. Do graduate programs in water resources engineering place adequate emphasis on the relatively new discipline of ecohydrology, which plays a significant role in sustaining riparian and upland ecosystems, particularly in arid and semiarid regions?

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