United States Geologic Survey
California Division
Land Development Department
346 Constitution Drive
Sacramento, CA 98221

To Keene Airport Planning Committee:

        Per your request, the USGS has compiled historical and current data about the proposed region for airport construction. As you asked, we forwarded information to Keene Cartographers for mapping purposes.

        This region is classified as a foothill region. Mountains are 20 km north of the proposed site. They peak at 2500 meters above sea level.

        Soil characteristics are relatively uniform across the grassland region. Duff layer is 0.10 - 0.25 cm, followed by 1 cm of topsoil, approximately 10 cm of mineral soil, and terminating at bedrock. The duff consists of organic materials rich in carbon, nitrogen, phosphorus, and potassium. The texture of the topsoil was course and classified as sand, with moderate permeability. The mineral soil contained 30% quartz, 55% feldspar, and 15% mica. Bedrock type consists mainly of intrusive granite, with deposits of quartz, feldspar, and mica. Drainage was observed as sinking to the depth of the water table (12 to 25 cm) displacing 0.25 cm per 2 cm of water.

        There are three rolling hills on the proposed site with 12, 15, and 20-degree slopes. This hilly region comprises a little less than 40% of the site. In hilly regions, soil layers are similar to those in the grasslands, but duff layers tend to be thicker, ranging from 0.25 to 1 cm.

        A river runs through the site at the northeast corner. The water depth and bed width varies with the seasons. On average, the bed is 9 meters across, with a depth of 6 meters. During drought conditions, the bed dries considerably and may hold 25% of its average volume. The river feeds some very small creeks and a substantial region of wetlands at the northeast region of the property. The water level in the wetlands occurs at 6 cm, but occurs much lower as the wetlands dry considerably in the summer.

        Earthquakes have occurred in abundance in this area, although none have had epicenters in the region being studied. On average, about 100 earthquakes happen every month, with an average magnitude of 1.6. 99% of these earthquakes have a magnitude lower than 3, indicating that most are insignificant in terms of structural damage. East, north, and south of this erosion, earthquakes larger than magnitude of 3 have occurred, but most have little effect on Keene, although rock fall in the mountains has been noted and produced some fatalities in hikers and climbers. The USGS recommends that all airport facilities be constructed with earthquake preparedness in mind, as magnitudes of 3.5 or higher (from earthquakes outside of Keene) have been experienced approximately once every four years.

        Flooding has been recorded in this region, extending far past the boundary of Highway 200. This is why the region west of the highway is grassland; flooding occurred every spring and tended to wipe out young trees and shrubs that had taken root in the region. In 1926, a dam north of Keene was built, which resulted in termination of seasonal flooding.

        During a recent USGS survey, archaeologists combed the area for remains, but found none indicating that the proposed site is a region of potential study. Therefore, Keene is permitted to construct airport facilities upon this site, without violating federal law regarding archaeological interest.

        Please contact us if further questions arise.

        Sincerely,
                Megan Falk
                USGS Land Development Manager