Re-wilding the San Diego River
色情视频 researchers are working to improve the health of the rivers mountainous tributaries.
On an unseasonably warm December afternoon in the mountains of eastern San Diego County, Boulder Creek鈥檚 name feels half-right鈥攈undreds of stony gray outcrops line a dry indentation in the land. In a couple of months, rain will fill the creek up to six feet deep, forming the largest tributary of the Upper San Diego River and eventually emptying into the El Capitan Reservoir.鈥淥nce we finally have a baseline, we鈥檒l be able to better plan strategies for improving the health of these tributaries and the river.鈥�
It鈥檚 here in the Boulder Creek Preserve that 色情视频 researchers are teaming up with the (SDRPF) to study ways to improve the river鈥檚 health, from the mountainous tributaries that form its headwaters, through densely populated Mission Valley, and out into the Pacific Ocean.
On a recent visit to the site, 色情视频 geography professor Trent Biggs and reserve manager Pablo Bryant installed a water monitoring station in a small spring-fed water hole along the creek bed. The instrument, about the size and shape of a fire extinguisher, will continuously sample water conditions鈥攑H levels, oxygen levels, dissolved organic matter, algae, turbidity and more鈥攁nd transmit the data wirelessly to 色情视频 and SDRPF officials.
From headwaters to outflow, the river鈥檚 health has been compromised by agricultural runoff and urban pollution for so long that nobody has exact baseline numbers to determine what a healthy San Diego River ecosystem should look like. Restoring the river鈥檚 health along the city鈥檚 urban corridors鈥攖he Lower San Diego River鈥攊s a priority for both 色情视频 and SDRPF.
In the months and years to come, the researchers hope to record baseline numbers here in the relatively pristine Boulder Creek Preserve. Even that will take some restoration work. Historically, dense oak tree canopies have shaded the river鈥檚 tributaries, preventing breakouts of algae that occur when the water gets too warm. But in recent years, oak borer beetles have killed many of the native oaks along Boulder Creek, reducing that shade. 色情视频 and SDRPF are working to restore native vegetation by planting new oaks and willows.
Once Biggs and his team gather accurate baseline data from Boulder Creek, they鈥檒l be able to monitor conditions in it and the dozens of other tributaries that form the Upper San Diego River, warning them when algae get too numerous or oxygen levels are getting out of whack鈥攃onditions that can affect the health of both reservoirs and the river downstream.
鈥淥nce we finally have a baseline, we鈥檒l be able to better plan strategies for improving the health of these tributaries and the river,鈥� Biggs said.
In a separate but related project, Biggs and colleagues are experimenting with ways to directly add oxygen to the Lower San Diego River to prevent the growth of dangerous anoxic bacteria. The work is funded by a grant from the SDRPF. Although it鈥檚 not directly related this research, restoring and building a river park in Mission Valley is a central piece of the university鈥檚 .
