Water Quality Workshop

Last Tuesday I went to the Elkhorn Slough Water Quality Workshop at the Moss Landing Marine Labs. I had signed up for it months ago when things were less busy, so when I received an e-mail reminder a few days before the event, my first reaction was that I could never afford to take half a day off. After thinking it over, however, I decided that it would be a welcome chance to get off the farm for a while—Moss Landing Marine Labs are located atop a sand dune with expansive views of the Monterey Bay, and the subject was one that is near and dear to my heart. I’m glad I went.

For those who aren’t familiar with Elkhorn Slough, it is a large brackish wetland whose main channel starts at Moss Landing Harbor (about 10 minutes south of us on Highway 1) and winds its way inland and to the North over six miles. Many of the issues facing Elkhorn Slough are similar to those affecting Harkins Slough, which borders our farm here in Watsonville, and our Lewis Road property is within the Elkhorn Slough watershed.

Mark Silberstein, the Executive Director of the Elkhorn Slough Foundation, gave a general overview of land use patterns in the watershed. And Andrea Woolfolk, from the Elkhorn Slough National Estuarine Research Reserve (ESNERR) gave a fascinating talk about the historical ecology of the region which included the revelation that there were a series of large, fresh water lakes in the area between Castroville and Salinas– an area that is all farmland now.

The most eye-opening part of the workshop came, however, when two scientists– John Haskins (ESNERR) and Ken Johnson (Monterey Bay Aquarium Research Institute)—presented the results of their separate water quality monitoring programs. As someone who farms within the watershed, I have a keen interest in how the farms on the hillsides surrounding the slough are affecting the water quality. What was shocking to me is the fact that the Nitrate levels washing into the slough from farms within the watershed pales in comparison to those coming in from the Old Salinas River.

Those of you who have been to the famous Phil’s Fish Market have driven over the Old Salinas River to get there. Before the creation of a man-made river mouth some four miles to the South, the Salinas River used to meander northward behind the sand dunes all the way to its original mouth North of Moss Landing Harbor. During the summer, or in drought years, when the flow isn’t strong enough to break through the sand barrier, the river reverts to its original channel and all of its contents are dumped into the Harbor—nitrates and all. From the harbor, the Old Salinas River flow is entrained on the flood tide into the main channel of Elkhorn Slough.

The problems associated with excess nutrients, like Nitrogen, are numerous.  Chief among them are algal “blooms”—the vast mats of brilliant green algae that are a common sight around the slough. These blooms can result in the depletion of oxygen available to aquatic animals and the mats themselves can smother vegetation on the banks of the wetlands.

The source of these nitrates in the Old Salinas River is almost exclusively from agricultural run-off.  Most of the farms in the lower Salinas Valley area are conventional vegetable and strawberry operations which use highly soluble, high analysis fertilizers. It is common practice to leave fields bare–listed up into beds ready to plant into in late winter/early spring.  With no cover crops in place to tie up the high levels of nutrients left over after harvest, they freely wash into open waterways when the winter rains come and end up in the Salinas River.

I left the workshop feeling more informed but slightly depressed. Agriculture in Monterey County is a four billion dollar industry. It is like a massive aircraft carrier that takes miles to turn and hours to stop. No matter how hard we work to prevent excess nutrients from leaving our farm–planting cover crops and buffer strips among other measures– we are still sitting in a little inflatable dingy by comparison.