 This is the Geysers Geothermal Field in Northern California. Enough electricity is generated here from steam wells to supply a city the size of San Francisco. The field has about 300 wells, 20 power plants, and generates about 1,400 megawatts of electricity. In this environmentally sensitive area, how are well sites chosen and designed? Today's practices solve yesterday's problems. Geothermal developers and governmental agencies work together to choose and prepare well sites at the Geysers. Once a geothermal company proposes a drilling location, the process begins. First, environmental concerns are addressed. Most companies have projects on state or private lands. Thus, they must meet requirements of the California Environmental Quality Act, or CEQA. Those with projects on federal lands follow similar federal mandates. For exploratory projects, the California Division of Oil and Gas is the lead agency. Otherwise, county governments take the lead role. Then, the division is called a responsible agency. In any case, an environmental document for CEQA is developed. It addresses significant environmental impacts. County and division CEQA timeframes vary. The streamlined division CEQA process takes up to 135 days. Under the division CEQA procedure, a project is evaluated by governmental agencies and other interested parties. Several group meetings are held, such as project site visits and public hearings. Concerns expressed here may result in many project changes. After all concerns are noted and documentation is finished, the state oil and gas supervisor or county official, depending on the project, may certify the environmental document as adequate under CEQA. All or part of the project may be approved or denied. Now, other public agencies responsible for issuing project permits may do so. Typically, these include the division of oil and gas, county governments, the local air pollution control district, and the regional water quality control board. The state departments of Fish and Game and Forestry and Sonoma State University act as interested parties. Biological, fire protection, and archaeological matters concern them. They issue no permits, but their standards must be met. Some of these agencies hold additional permit hearings. Usually, permit decisions are issued promptly because of interagency CEQA participation. After the environmental review is completed and a company receives state and local permits, well-site design begins. A question facing early field developers was, where should the wells be drilled? The matter is still critical today. When modern field development started in the 1950s and 60s, the answers seemed obvious. Drill on the flat hillside terraces. So, that's where the company's drilled. And some of the wells blew out. The problem wasn't with the wells, but with the well sites. Almost to a site, the flat terraces proved to be parts of active, deep landslides, still slipping periodically down slopes in the field. As tons of earth moved and pressed against some wells, well pipes were bent, sheared, and steam escaped. Thus, the wells blew out of control. Clearly, changes were needed in well site selection and preparation practices. Today, division regulations require wells to be sited in stable areas, which are often rocky knolls or ridge lines. Before well site construction begins, a geotechnical study is made. Company geologists review aerial and geological maps. They study well site geology, undertaking well-boring and trenching activities to learn subsurface conditions. Here at a potential well site, I look for shallow bedrock, which will provide a firm foundation, and landforms that are not indicative of landslides, which are found throughout the geysers area. Hummicky terrain and springs are features that we wish to avoid in finding a good site. Other potential dangers include surface or subsurface drainage problems, rock type changes, and faults. A civil engineer designs the well site to mitigate the hazards. This one acre site is a typical geysers drill pad. Two wells will be drilled here. The geotechnical study and the well site engineering plan are submitted to the division of oil and gas and of county officials. Both must approve the study and the plans, and issue construction permits before any well site work can begin. Good afternoon, Ken. Good afternoon, Mark. Here's the geotechnical report for our new well site. Fine. Thank you very much. I'll add this to the site plans. When it's time to begin construction, a site is staked and cleared of vegetation. Then, a critical trench called a key is cut at the base of the site. The key acts like a retaining wall, preventing the well site from moving forward. Because of the mountainous regions and the geysers and the areas of instability, operators will choose knolls or ridges upon which to build drill sites. Considering this a ridge, the operator will take off the top and through balance, cut, and fill will build a site. Down at the toe is a keyway, which will be built two to five feet in depth, approximately 12 feet in width. From this point, material will be added until they reach the location of the drill site. A division engineer inspects the key. It must be free of faults and drainage problems. The key must extend two feet or more into bedrock or competent rock, which is outlined by the pick. If everything is satisfactory, the key is backfilled and the fill material is compacted. No large pieces of organic matter like roots and branches are packed into the key. These would decay and weaken the structure. The well site is cut into small terraces that extend down to the solid or competent rock. Drains are added if necessary. Next, the terraces are backfilled and this material is compacted up to the final well pad elevation. We'll consider now water control on the pad itself. Considering this to be the sump, we're looking down on the pad now. This being an access road, this being a backslope, water would be coming down naturally from the slope on the pad itself, but basically you don't want to direct toward the sump. So what you want to do is to run off. You have a berm around your well site entirely to control your runoff. You would have a down spout, an outlet here, directing all of your water to that point from the pad. From the back, you might have a bench. You would probably have a collector here where water would be caught, chandled along, collected, brought along, and out again in a controlled sequence. Four to five steam wells are directionally drilled from most modern well sites at the geysers. Twice annually, before and after the winter rains, division engineers check all well sites in the field. This care has increased environmental compatibility and site stability in the field. A testimonial to the program is the fact that no wells have blown out at the geysers since 1975.