The sixth annual San Diego River Days — “two weeks of discovery and giving back to the San Diego River”— are scheduled May 9 to 17, with the whole thing kicking off at the Dog Beach paw print at the end of Voltaire Street in Ocean Beach on May 9 at 8 a.m. The Dog Beach cleanup follows at 9 a.m.; subsequent activities include a bike ride, a hike in a proposed wilderness area, a river garden open house and a look at the river’s future education center site. You can find out more about the Days’ 30 events by accessing sandiegoriver.org and clicking on the appropriate link. What you can’t do is hope to discover the river’s significance throughout local history, at least not firsthand. After all, we’re talking a length of 52 miles, stretching from Santa Ysabel in east San Diego County to the El Capitan Reservoir to Lakeside, Santee and Mission Valley to Ocean Beach. The waterway’s less-than-pristine condition in some areas stems from decades upon decades of urban runoff and neglect, although myriad kayaking and fishing spots underscore the river’s cultural significance. While the San Diego River Park Foundation eagerly cites the river’s vices and virtues, it’s quick to point out its proud place in the city’s past. Our present-day Downtown, in fact, depended largely on the river’s presence for its growth — in the mid-19th century, when Broadway was known as D Street, the river served as the main water source “One way to look at it,” explained foundation director Rob Hutsel, “is that it was like a big delta. The river would come out of the mountains and through the valley and then spread out in a big, broad floodplain.” Fifty-two miles of sediment would wash into San Diego Bay; once it got there, the contents then backed up into a separate body of water the Spanish settlers called False Bay — the name was meant as a warning to newly arrived parties not to enter it. The Spanish, in fact, were creating settlements in the present-day Downtown since 1759 — and they chose that spot due to the availability of water from the San Diego River. By 1850, the year California attained statehood, area maritime trade was booming; soon after, Alonzo Horton saw fit to create a “New Town” city core at the spot we know today as Downtown. “The folks wanted the seat of government to be Downtown,” Hutsel said, “so they stole it from Old Town and took it down there. In time, the San Diego River actually continued to supply water Downtown, so [Horton’s parties] would take it there in buckets and barrels and that kind of thing.” In time, Hutsel continued, pump stations would extract water for mechanical transport to the city core. The pumps were turned off in 1920, Hutsel said, “because the city was building reservoirs upstream and didn’t need to pump the water anymore.” Logistically, things have stayed stable since then — but the point is that history played into those logistics longer than anyone around here can remember. River Days may be a heckuva lot of fun, but it’s also a testament to a Downtown who in no small part owes its regional stature to an indispensable waterway.