Wet/dry mapping provides a low-cost, comprehensive snapshot for monitoring flow conditions in rivers with interrupted perennial (spatially intermittent) surface flow. When used in conjunction with more traditional point-specific stream flow or groundwater measurements, it provides a better understanding of hydrologic systems at the broad landscape or watershed scale. Through use of trained volunteers, we mapped reaches with surface water during the driest time of year to track annual variation in length and location of perennial flow. Data from 12 years of wet/dry mapping on the San Pedro River in Arizona, USA, showed 62 reaches with surface flow in every year, totaling 32% of the river length through the San Pedro Riparian National Conservation Area. They also show areas with high year-to-year variation in flow length, which indicate changes in local groundwater conditions and may provide early warning of ecological changes. Data and maps from this project have been useful for a wide variety of conservation, management, and research efforts.

The San Pedro River originates in Sonora, Mexico, and flows north through Arizona, USA, to its confluence with the Gila River. The 92-km Upper San Pedro River is characterized by interrupted perennial flow, and serves as a vital wildlife corridor through this semiarid to arid region. Over the past century, groundwater pumping in this bi-national basin has depleted baseflows in the river. In 2007, the United States Geological Survey published the most recent groundwater model of the basin. This model served as the basis for predictive simulations, including maps of stream flow capture due to pumping and of stream flow restoration due to managed aquifer recharge. Simulation results show that ramping up near-stream recharge, as needed, to compensate for downward pumping-related stress on the water table, could sustain baseflows in the Upper San Pedro River at or above 2003 levels until the year 2100 with less than 4.7 million cubic meters per year (MCM/yr). Wet-dry mapping of the river over a period of 15 years developed a body of empirical evidence which, when combined with the simulation tools, provided powerful technical support to decision makers struggling to manage aquifer recharge to support baseflows in the river while also accommodating the economic needs of the basin.

Groundwater pumping along portions of the binational San Pedro River has depleted aquifer storage that supports baseflow in the San Pedro River. A consortium of 23 agencies, business interests, and non-governmental organizations pooled their collective resources to develop the scientific understanding and technical tools required to optimize the management of this complex, interconnected groundwater-surface water system. A paradigm shift occurred as stakeholders first collaboratively developed, and then later applied, several key hydrologic simulation and monitoring tools. Water resources planning and management transitioned from a traditional water budget-based approach to a more strategic and spatially-explicit optimization process. After groundwater modeling results suggested that strategic near-stream recharge could reasonably sustain baseflows at or above 2003 levels until the year 2100, even in the presence of continued groundwater development, a group of collaborators worked for four years to acquire 2250 hectares of land in key locations along 34 kilometers of the river specifically for this purpose. These actions reflect an evolved common vision that considers the multiple water demands of both humans and the riparian ecosystem associated with the San Pedro River.

We surveyed the amphibians and reptiles of the Whetstone Mountains in southeastern Arizona using a combination of intensive small-area plots, extensive walking searches, trap arrays, road-driving, spot checks, and review of previous records. We found 43 species within the National Forest boundary and within 1 mile of the boundary. Composition of the herpetofauna is typically Madrean and included 5 anuran, 2 turtle, 21 lizard, and 14 snake species. Previous records from the study area documented only 15 species. Quantitative results of intensive and extensive searches provide additional baseline data that could be used for future monitoring efforts. Resumen Se realizó un muestreo de los anfibios y reptiles de las Montañas Whetstone en el sudeste de Arizona utilizando una combinación de revisión intensiva de parcelas pequeñas, búsquedas extensivas al caminar, matrices de trampas, búsqueda desde un vehículo, muestras hechas al azar, y revisión de registros anteriores. Se encontraron 43 especies dentro de los límites del Bosque Nacional y en 1 milla fuera del límite. La composición de la herpetofauna es Madrense típica e incluyó 5 especies de anuros, 2 de tortugas, 21 de lagartijas, y 14 de culebras. Registros anteriores del área de estudio documentaron solamente 15 especies. Los resultados cuantitativos de muestreos intensos y extensos proporcionan datos adicionales de referencia que pueden ser útiles en monitoreos en el futuro.