Countless cities have harnessed rivers as focal points for civic renaissance and tourism gambits. Memphis’s Mud Island and Minneapolis’s Mill District are but two of the nation’s riverside destinations. San Antonio’s River Walk, by dint of its age, is a more iconic example. First envisioned in the 1920s and constructed with federal funding under FDR’s New Deal, the River Walk became as much a handle for San Antonio as the famed Alamo.¬†While creating a great riverine attraction on the surface may appear straightforward, it involves much more than meets the eye. Maintaining San Antonio’s tourist and civic goldmine is not simply a matter of maintaining the infrastructure at water’s edge. Rather, at this time of year, especially in droughts, it is a matter of…