Poor Management Leads to Excessive Erosion

During a “normal” rainy season, if there is such a thing, the water in our neighboring Harkins Slough can, in places, turn the color of a cup of coffee with half & half mixed in. After a series of strong storms, this turbidity typically lasts for a few weeks before the silt and clay particles settle out and the water returns to its normal grayish-green clarity. This year, however, from one end to the other, the slough has been a cloudy brownish color for months. The culprit, as it is every year, is erosion from the fields that surround the slough on all sides. Five straight years of below normal rainfall have meant that growers have become lax in their management practices. Examples of poor stewardship abound–raised beds aligned straight down steep hillsides; cover crops planted much too late or not at all; ditches, drainage structures and settlement basins poorly maintained and failing.

Directly to the west of us on the other side of the slough is a property that we know well. We still refer to it as the Bloom-Rite parcel because long ago, a company by that name, managed by a friend of my uncle, used to grow flowers on it. When we made the decision to expand our operation, before purchasing the Lewis Road property that we now own, we tried to buy it together with my cousin Josh. As part of an effort to educate ourselves as much as possible before bidding on it (it was sold at auction) we walked the property with Rich Casales, the Natural Resources Conservation Service agent who had designed an elaborate drainage system for the property during one of his first assignments. The system, which was largely still intact when we toured the property, consisted of a drainage pipe, four feet in diameter, that was designed to carry runoff from the upstream neighbor, as well as water collected from several drains on the parcel itself, safely down to the slough. Needless to say, when the auction day came around we were outbid and the property was purchased by someone who owns several other nearby large parcels. The following year, an herb operation set up several acres of greenhouses on the flat central portion, and the rest of the property was leased into strawberry and vegetable production.

From the vantage point of our home ranch, nearly a half mile away, we could see that problems were developing early this rainy season on the old Bloom-Rite parcel. On half of the steep, sandy, back hill, which had been planted into a cover crop much too late, deep rills and gullies were clearly visible stretching from the base nearly three quarters of the way to the top. When they disced down the other half of the field, which is partially obscured from our view by several large eucalyptus trees, and attempted to plant a cover crop in late December, we knew it could only mean trouble.

On a recent Sunday, I decided to paddle across the slough with my children via canoe and kayak to investigate. Upon bushwhacking our way up the bank 200 feet or so through blackberry and poison oak, the first evidence of the tremendous erosion that had occurred came into view. On the terrace where a railroad track passes mid way up the steep bank beneath the Bloom-Rite parcel, numerous great fans of sand where deposited, some big enough to cover the tracks entirely. When we climbed the top half of the bank the true extent of the damage became clear. The drains had apparently failed entirely because a vast gully had developed, 20 feet deep and over 50 feet wide in places, that had climbed nearly to the top of the field leaving sections of the drainage pipe lying disconnected and useless in its bottom. In the fields on either side deep gullies radiated away up the hillside—some over 8 feet deep. The vast amount of soil removed from the field in these gullies and the central “canyon” was deposited first in the form of sand along the bottom edge of the field and onto the railroad tracks. The finer silts were carried out to form a growing peninsula along the banks of the slough. And the finest clay particles are largely still in suspension, helping to account for the coffee colored water.

It’s been a difficult rainy season for all of us and I hesitate to jump on another growers misfortune, but the mistakes here were numerous and glaring. Cover crops do a great job of stabilizing soil particles and increasing water infiltration but only when they are planted correctly and well established. From the looks of things, the cover crops on most of the parcel weren’t planted until late November—much too late considering the steep slopes and erosive soil type present there. When the portion of the back hill was planted in December the last tillage pass in preparation was performed straight up and down the hill, leaving dips and ridges for the water to follow which eventually turned into many of the rills and gullies present now. And lastly there is the problem of the greenhouses. When you cover several acres with plastic, the water that falls there has to go somewhere. Putting greenhouses atop a steep sandy hillside without a well-maintained, fully functional drainage system in place is irresponsible in the very least.

I can’t pretend to have answers for problems like these. It would be nice if growers would consider their stewardship responsibilities a matter of pride, so that failures such as those on the old Bloom-Rite property would be an embarrassment to be avoided at all cost. But in this version of impersonal, industrialized agriculture that dominates down here, too often that doesn’t seem to be the case. A combination of increased education and enforcement could go a long way to protect water quality and maintain good farmland for future generations.