Applying Hydrology to Land Management on the Valles Caldera
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ince 2004, the Valles Caldera the Jemez River’s East Fork to 11,254 feet SNational Preserve (VCNP) in on Redondo Peak, the highest dome in the Applying the Jemez Mountains of northern caldera (see map, right). VCNP forms a New Mexico has hosted extensive field single watershed draining from a breach in hydrology research by scientists from the caldera wall to the Jemez River’s San Hydrology the Center for Sustainability of semi- Diego Canyon, southwest of the preserve. Arid Hydrology and Riparian Areas (SAHRA) at the University of Arizona. Legacies of Human Activities With the development of a detailed Humans have utilized the VCNP region to Land hydrologic understanding of VCNP’s for at least 10,000 years, harvesting plants climate, geology, soils, vegetation, and and wildlife for food and collecting high- hydrology, preserve managers have grade obsidian for tools and weapons. Management begun to incorporate research results As a private land holding, livestock into their management planning for grazing and logging operations dominated rangelands, forests, and watersheds, human land use in the 19th and 20th on the Valles including specific programs such as centuries, significantly impacting the livestock grazing and management of watersheds and riparian ecosystems. fisheries and wildlife populations. Extensive, long-term overgrazing by sheep (pre-World War II) and livestock Caldera The Preserve (post-1950s) led to substantial degradation The Valles Caldera Preservation Act of streambanks and water quality; even (PL 106-248), passed by Congress in today the major streams of the preserve National 2000, provided for the acquisition of the are listed as “impaired” by the New privately owned Baca Ranch. The act Mexico Environment Department, with designated these acquired lands as the total maximum daily loads issued for VCNP, and created the nonprofit Valles temperature and turbidity as a result of Preserve Caldera Trust to manage the 88,900- past private ranch management practices. acre tract. The preserve was established In addition, extensive clearcutting of the Robert R. Parmenter – to protect and preserve the scientific, VCNP by the New Mexico Land and Valles Caldera National Preserve scenic, geologic, watershed, fish, wildlife, Timber Company occurred in the 1960s historic, heritage, and recreational values and 1970s (see photos), accelerating of the area, and to provide for multiple soil erosion and contributing to the use and sustained yield of the renewable turbidity loading of the streams. Today’s resources within it. VCNP operates forests are dense with second-growth as a working ranch and is to become stands of young pine, fir, and spruce, financially self-sustaining by 2015. which pose a substantial influence The VCNP land is a collapsed magma on fire risk and watershed health. chamber (caldera) approximately 15.5 miles across, and incorporates Hydro Research Informs multiple resurgent lava domes that Management Repeat aerial photography of Redondito Peak, rose following the chamber’s collapse In this water-limited montane ecosystem, VCNP, showing logging impacts. Left: prior to around 1.25 million years ago. VCNP is VCNP land managers are incorporating logging in 1963; center: after logging in 1975 characterized by these forested domes both the constraints and opportunities (showing logging road system); right: near- closure of dense second-growth tree canoopy and grassland valles (valleys). Elevation illuminated by new research. Given the in 2005. ranges from 7,930 feet at the outflow of poor condition of the preserve’s extensive 1963 1973 2005 22 • March/April 2009 • Southwest Hydrology second-growth forests, managers have discharge from the Valles Caldera begun to thin and burn the “dog hair” preserve by approximately Santa Fe Rio Arriba County thickets of young Ponderosa pine and 10 to 20 percent. NEW MEXICO white fir in an effort to reduce catastrophic Sandoval County N This enhancement of Valle San Antonio fire risk and improve wildlife habitat. San Antonio Creek “ecosystem services” to Recent measurements have shown that Valle Toledo Valle Santa Rosa San these dense, second-growth forests society in the Rio Grande Antonio Creek valley has significant San Antonio Los intercept much of the winter snowfall Mountain monetary value. VCNP Valle Seco Cerro del Abrigo Alamos County before it can hit the ground, and as a Valle de streams produce around los Posos result, nearly 50 percent of the snow water Valle Jaramillo 20,000 acre-feet of Sulphur Creek Cerro del equivalent (SWE) sublimates and is lost Jaramillo Creek Medio from the terrestrial hydrologic cycle. water each year: a 10 Redondo Border percent increase in La Jara Creek Redondo Peak Valle Grande stream discharge would Redondo Creek By implementing equal 2,000 acre-feet. Legend Banco Bonito East Fork Jemez River Elevation (m) At current water rights 4 Roads 4000 thinning prescriptions, Streams prices (the city of Rio County Lines 3000 VCNP 2000 managers intend to Boundary Rancho, New Mexico, 0 3 km 6 km increase the amount recently purchased of water available water rights for $11,000 Location of the Valles Caldera National Preserve in New Mexico. per acre-foot), the capital snowmelt and summer thunderstorm to the terrestrial value of 2,000 acre-feet would equal events will further increase the $22 million. If leased at 10 percent of hydrologic cycle. capabilities of this toolbox to accurately capital value per year, this would equal an predict short-term trends in grassland annual water benefit worth $2.2 million However, new research has also quantified productivity for grazing programs. These to downstream farmers, ranchers, and how snow and SWE are distributed in models also can be applied for fire risk urban residents. Concomitantly, the microsites around trees. A field survey assessment and fuels management. of 900 points found maximum snow financial benefit of reduced fire risk accumulation occurs under canopy and increased forage for wildlife and Looking Ahead livestock from forest thinning further densities between 25 and 45 percent, The recent research has added enhances the collective value to society. corresponding to about 20 percent greater significantly to the knowledge base of SWE than in open areas (Veatch, 2008). Hydrologic principles also are being VCNP managers, with direct applications From these data, mathematical models incorporated into rangeland productivity to forest and range management. Future are being developed to maximize SWE assessments and forecasts for elk and models, incorporating remote-sensing, retention (minimize sublimation) through livestock grazing on the VCNP. Currently, geographical information systems, and forest-thinning prescriptions. For each cattle stocking rates are predicated on real-time monitoring of climate and forest stand of a given age, size, and available spring forage production, soil vegetation dynamics, will greatly enhance density structure on a known slope, aspect, moisture profiles, and 3-month climate our capability to manage public lands in and elevation, there is a unique solution forecasts. Satellite-based MODIS remote- a sustainable and economically efficient to optimize open space (allowing snow sensing imagery are used to evaluate fashion. Continued development of to reach the ground) and still provide forage biomass on 250 x 250-meter basic scientific principles in hydrology shade to reduce sun- and wind-driven pixels on a daily basis, and managers and science-based applications to sublimation. By implementing these can examine increasing and decreasing watershed management issues will thinning prescriptions, VCNP managers trends in forage to make real-time ensure the successful management intend to increase the amount of water decisions on livestock distributions and and long-term sustainability of the available to the terrestrial hydrologic movements, such as pasture rotations. natural resources of the Southwest. cycle, enhancing growth of trees, shrubs, grasses, and forbs for wildlife food Contact Bob Parmenter at Future additions to these applications will [email protected]. and habitat, and potentially providing include use of NEXRAD data to estimate additional streamwater discharge during storm-specific precipitation amounts and spring snowmelt for downstream users. distributions, coupled with forage-growth Reference Preliminary estimates suggest that Veatch, W., 2008. Quantifying the effects of forest models to forecast short-term (2-week) canopy cover on net snow accumulation at a using these forest thinning prescriptions changes in forage amounts. Hydrologic continental, mid-latitude site, Valles Caldera could reduce snow sublimation by up models that depict watershed dynamics National Preserve, New Mexico, USA. M.S. thesis, Univ. of Arizona Dept. of Hydrology and to 50 percent, thereby increasing stream and soil-moisture changes following Water Resources. March/April 2009 • Southwest Hydrology • 23.