Exactly so on on Owen's. But water flows to Owen's about the same time it flows to Hetch Hetchy, and is used in LA on about the same annual pattern as in San Fran. So the answer on Hetch Hetchy is true, but simply begs the question, which is "Why there?"
There is no "Why there?" about fresh water at Owens Lake. There never has been, historically. Owens Lake was brine. Farmers used the water before it got to Owens Lake and the lake level was already dropping because of irrigation diversions before LA bought the rights to the diverted water. Today the major diversion from the Owens River is between Independence and Big Pine. Fresh water is stored above that point in many mountain reservoirs (June Lakes, South Lake, Sabrina, etc.), in valley reservoirs (Crowley, Pleasant Valley, Tinemaha, and Hiawee-which is below Owens) and in lakes in the mountains around the LA basin. The reservoirs around LA have two main purposes: keeping storms from flushing local mountain mud, gravel and boulders into the suburbs and storing water from distant places like the Owens Valley and the Colorado River.
Today the lower Owens gets about 40 CFS of water that is pumped back into the canal at the head of Owens Lake before it picks up salt(Google "Lower Owens River Project"). Water delivery through the Owens River channel near Bishop is often as high as 600 CFS when water is being delivered downstream for storage or use. It goes through the canal around Owens Lake.
Dale B. Dalrymple