Just 950 feet from the Bolinas Ridge Fire Road—a mere three-minute walk—Marin Municipal Water District (MMWD) rangers found the evidence of yet another illicit marijuana planting on the watershed. What might an unsuspecting hiker or biker, straying from the well-used fire road, be likely to encounter?

At a minimum: evidence of an encampment, food and trash; propane tanks; tools and equipment for planting and irrigation, including water lines leading to often distant water sources and even crude cisterns for on-site storage; a variety of firearms; and human waste. One might also find evidence of herbicides and tools to remove native vegetation; cut or girdled trees and other damaged native plants; irrigation runoff laden with fertilizers, pesticides, and other pollutants; traps for wildlife killed for consumption . . . and marijuana plants numbering in the thousands, dispersed in a mosaic hidden in the forest understory or mixed among other native vegetation.

(For photos of a typical encampment, visit the US Forest Service Region 5 Flickr page.)

On March 7, an audience of 35 attended a meeting co-sponsored by Tamalpais Conservation Club (TCC) and Marin Conservation League to hear MMWD Chief Ranger Bill Hogan, Marin Sheriff’s Deputy Bob Crowley and colleagues describe their ongoing battle to keep ahead of the exponential growth of marijuana cultivation on the district’s watershed lands.

The environmental damage and financial toll on MMWD have been profound. Soils are damaged by erosion. Native habitats and water quality are threatened by the growers’ irrigation methods and uncontrolled use of chemicals. The costs and manpower required to combat the problem and the potential hazards to both personnel and the public keep mounting even as strategies to combat the invasion have advanced.

Attendees learned that California is #1 in the United States in growth of marijuana, 70 percent of which is grown on public lands. Although Marin is no Mendocino or Napa County, where four deaths were recently reported as a direct result of illegal marijuana cultivation, efforts to grow marijuana plants on water district lands have grown in recent years. In 1982, 1,430 plants were eradicated. By 2006 that number has risen to 26,000. In 2010-2011, 23,000 plants were removed. As the stakes rise, so do the risks.

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Impact on district rangers

Bill Hogan has been a ranger with MMWD since 1977. In the 1980s and 90s, he saw growth in outdoor recreation transform the 22,000-acre Mount Tamalpais watershed from the quiet backyard of Marin County to a major destination for outdoor recreation enthusiasts. Now it has become a major destination for illicit marijuana growers. With this change has come the need for district rangers to spend increasing amounts of time in planning, incident action and clean-up of marijuana “grows.” The burden of this work has been magnified as their numbers have shrunk from 11 to six at the present time, keeping them from doing other essential work on the 29-square-mile watershed. The problem would be impossible to abate, he said, without the support of the Marin County Sheriff’s Office and cooperation of colleagues in the National Park Service, who face similar problems on federal park lands.

According to Bill, tracking the marijuana grows in the district’s watershed requires constant vigilance. Although grows are concentrated primarily in Bolinas Ridge areas west of Kent Lake, other sites have been located in the Nicasio and Soulejule watersheds.

Detection of new sites is increasingly difficult. Although aerial overflights are used, the planting sites are hidden by existing vegetation. Known, established sites must be rechecked frequently for signs of new clearing, irrigation lines that can often stretch a half-mile to a water source, and habitation. Reports by watershed visitors of suspicious activity or persons must be checked. Once a possible site is discovered, staff must scout thoroughly, gathering and documenting evidence and intelligence as to growers’ activity. The next step is developing a safe and well coordinated plan for eradication and, if possible, apprehension of the individuals. This latter action is extremely difficult and potentially hazardous: growing sites are scattered over large areas; and caretaker personnel (mostly undocumented aliens) move in and out of the area, having been dropped by a variety of vehicles (including boats) at night and on different days and establish hiding places.

Since MMWD rangers are unarmed, only the deputy sheriffs can apprehend individuals. The deputies’ work is complicated by the danger of encountering potentially armed individuals as well as by rules in the Penal Code governing the evidence needed to charge misdemeanors and felonies.

When a misdemeanor, such as trespass, illegal fires, or carrying a concealed weapon, is involved, the individual may only be ticketed and released. Such crimes carry a maximum 120-day jail sentence. Ticketed misdemeanor suspects often simply disappear, and recidivism is high. For a felony prosecution, the code requires that at least 1,000 marijuana plants be under cultivation, and there must be observations of the suspects tending to the plants and extensive photo-documentation of the site and plants with the root-ball intact.

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What progress has been made, and what does the future hold for District lands?

In addition to the impact on ranger resources, the fiscal impact on the district is substantial, according to Bill. For example, the cost of a recent clean-up of one site alone was estimated at $34,000, which involved gathering up a wide array of equipment and waste and exporting it out by helicopter. This does not include the cost of restoring soils or native vegetation and wildlife habitats. He expressed guarded optimism that improved intelligence has yielded some success, if only in minimizing the damage to the watershed. Surveillance techniques, as he described them, are “cutting edge” in approach.

At the same time, as abatement techniques have become more sophisticated, so have the strategies of the growers, most of whom are associated with Mexican drug trafficking cartels. Post-9/11 improvements to border security have now made it more efficient for the cartels to smuggle people over the border to tend marijuana grows in California than to smuggle Mexican-grown crops into market areas north of the border. And the demand has only increased. The MMWD watershed is not the only land in the Bay Area that has been targeted by growers; federal parklands, remote privately-owned ranchlands, East Bay Regional Park, and others have been victimized as well.

In response to questions from audience members asking what they could do to assist, Bill responded that individuals can call the Sky Oaks Watershed Headquarters at (415) 945-1181 to report suspicious activity (persons carrying camping gear, shovels, other equipment, etc.).

More than one member of the audience suggested that this problem deserves the ongoing attention of the MMWD Board and that MMWD staff should reevaluate the risks associated with essential ranger patrol actions as well as the reduction in ranger personnel. These decisions have proved costly in view of the increased workload brought on by this dangerous and environmentally damaging illegal activity on the watershed.

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Link to May 2012 article in Outside Magazine on marijuana in Mendocino National Forest