A geographically-based framework for landuse suitability assessment and land capability classification in Ibulao watershed, Philippines was developed and used in this study. Landuse suitability assessment was based primarily on soil erosion, the results of which were compared with the outcome of suitability assessments based on two land classification systems in the Philippines. The Ibulao watershed was subdivided into 10-ha cells, and each cell was independently evaluated with the aid of a geographic information system called MAP. The soil erosion rates for each cell were estimated using the MUSLE. The surface runoff and peak runoff rates were simulated using an infiltration-kinematic routing model, an event-based stochastic rainfall duration model, and the CREAMS model. The land capability classification was based on erosion index representing the inherent soil erodibility of a cell computed on the basis of runoff erosivity factor, soil erodibility factor, and the slope length-gradient factor. The results of capability classification were used to identify the different alternative uses of any cell in the watershed. The framework described in this study for landuse suitability assessment and land capability classification illustrated potentials for applications to the management and allocation of land resources in the Philippines. An erosion-based landuse assessment and land capability classification appears to be a better alternative to a slope-based system as far as the following are concerned: (1) identification of landuses which would not jeopardize the long term productivity and stability of an area; (2) a more accurate and meaningful land capability description and classification; and (3) making more lands available for various alternative uses by using criteria such as soil erosion which can easily be manipulated.

Thesis (M.L.A.) -- University of Texas at Arlington, 2008.

Watershed ecosystems consist of numerous resources which have important environmental, social, cultural, and economic values. The mutual existence and interaction among different resources within the watershed ecosystem calls for a multiobjective watershed resources management analysis. These objectives are often uncertain since they are based on estimation and/or measurement data. Probabilistic methods or fuzzification are usually the methods used in modeling these uncertainties. Selection of the best decision alternative is based on using some Multiple Criterion Decision Making (MCDM) technique. Through simulation in this dissertation, we examine the probabilistic model to address the watershed management problem. In particular, the distance-based methods, which are the most frequently used MCDM techniques, are employed in the problem analysis. In most cases, several interest groups with conflicting preferences are willing to influence the final decision. In our study, a new method is suggested to incorporate their preference orders into the DM's final preference. The application of MCDM techniques combined with stochastic simulation and conflicting preference orders is new in the watershed management literature. Detailed analysis and comparison of the numerical results will help to decide on the suitability of the MCDM technique in watershed resources management. In particular, our numerical results indicate that in practical applications the best alternative selection is significantly influenced by the uncertainties in the payoff values. Hence, in situations where suitable data are available, our methodology is highly recommended.

The goal of this research was to develop a watershed-scale model for predicting changes in plant species distribution and abundance (phytogeography) that might occur as a result of changes in climatic factors with global warming. The model was designed: 1) to be spatially explicit and applicable across the entire watershed; 2) to apply to a number of particular species rather than general vegetation types; 3) to predict abundance as well as presence/absence; and 4) to work with simple environmental data, but reflect a biological rationale. Correlations were sought between current phytogeography in the watershed and the synoptic climate variables mean annual temperature, total annual precipitation and cool-/warm-season precipitation ratio. The contribution of edaphic and topographic variables to correlative models was examined and found to be negligible. The correlations established for current conditions were extended to hypothetical future conditions of changed climate in which the values of the variables were manipulated and the model run to produce predictions of altered future phytogeographies. Twenty-seven different hypothetical climate scenarios were modeled, incorporating a 1°C or 2°C rise in temperature with as much as a 10% increase or decrease in seasonal precipitation. Spatial articulation of the model was achieved through raster analysis of gridcell based data layers in a geographic information system. Primary input layers were a series of high-resolution (360x360m) interpolated climate-variable surfaces and a geographically referenced database of plant species presence and abundance derived from an aerial videography sample of the watershed. Logistic regression analysis was used to calculate, for a given set of conditions, the most probable state (present/absent) and abundance class for ten plant species at each grid-cell location in the watershed. Fragmentation of species' distributions before and after change was examined. Results for all studied species showed marked changes in distribution and abundance with temperature rise. Desert species will likely increase in abundance and occupiable area as forest and woodland species decrease, but much depends on the interaction of precipitation with temperature. Model predictions are conservative compared with paleoecological evidence of past changes.

Two piñon (Pinus edulus) tree-ring chronologies developed on each of three substrates (sandstone, shale, and alluvial fan deposits) in southern Utah for the period 1702 to 1997 demonstrate that geologic substrate affects dendrochronologic streamflow reconstructions. Chronologies from alluvial fan deposits explain the most variance of cool-season (October 1 to May 31) flow with an adjusted coefficient of determination (Rₐ²) equal to 0.59. Chronologies from sandstone deposits account for 52 percent of the variance, while those on shale deposits account for 45 percent. Correlation coefficients among the three substrates are significantly different at the 95% confidence level. The highest single-site annual discharge reconstruction (October 1 to September 30), Rₐ² = 0.25, is provided by chronologies from shale deposits. The highest substrate-pair annual discharge reconstruction, Rₐ² = 0.27, is provided by chronologies from alluvial fan deposits. The highest summer discharge reconstruction(July 4 to September 3), Rₐ² = 0.14, is provided by chronologies from sandstone. Over 90 percent of the summer reconstructions are below Rₐ² = 0.10.

OWRT Project No. A-069-ARIZ / Agreement No. 14-34-0001-6003 / Project Dates: July 1975-September 1977 / Acknowledgement: The work upon which this report is based was supported by funds provided by the United States Department of the Interior, Office of Water Research and Technology, as authorized under the Water Resources Research Act of 1978. / In dealing with water management methods for a watershed possibly subject to intensive development in the future, such as the Sonoita Creek Basin in Arizona, a model of the hydrologic system is the only possible link between the hydrologist and the systems engineer. The water balance picture that was taken by the hydrologist has to be advanced up to a point in which the response of the aquifer considered, to different water policies, will be known. At this point the integration between the environment and its management can be properly addressed. From a standpoint of the hydrologist, a model is therefore the overall goal of his study. Such a model will enable him to simulate the relationships between recharge, discharge and ground-water elevation. Consequently, a water balance model was calibrated, and a working routine with the model was developed that was used by the systems engineers.

Four artificial tracers were applied to a small headwater catchment in south western British Columbia to study runoff generated from topographically distinct landscape units. The seven hectare catchment is located in the University of British Columbia Malcolm Knapp Research Forest at low elevation (190-280 masl). A weir, multiple tipping bucket rain gauges and several piezometers were used to collect hydrological data. Three separate landscape units were identified based on topography, soil properties and proximity to the stream. The units included an area of shallow slope and deep soil, a riparian area along the intermittent stream channel and an area of very shallow soil with bedrock outcrops on a steep slope. Tracers used included rhodamine-WT, uranine, sodium chloride and potassium bromide. A suite of ion selective and fluorometric probes were used along with automated water sampling to monitor tracer breakthrough. The collected samples were analysed in the lab to validate the field measurements. Tracers were dissolved in solution and applied aerially with a backpack sprayer at the onset of forecasted precipitation events to facilitate rapid infiltration into the soil. The first application took place January 4th, 2006. Measurements were then taken continuously until March 20th, 2006, when a second round of tracers was applied to the landscape units. During the first measurement period, 532 mm of precipitation fell below the forest canopy over 75 days. During the second 78 day measurement period, 290 mm of rain fell. It was found that the overall wetness of the catchment affected travel times significantly. Large storms during the first, significantly wetter, application period exhibited similar lag times from peak event discharge to tracer arrival between the different landscape units. During small precipitation events and under dryer conditions, travel times were greatest in the area of shallow slope and deep soils. These lag times are indicative of longer pathways and perhaps the non-initiation of preferential flow below certain thresholds. In general, it was concluded that delineating catchments into groups of similar landscape units based on physical characteristics may be a promising new approach to explaining catchment runoff response.

Four artificial tracers were applied to a small headwater catchment in south western British Columbia to study runoff generated from topographically distinct landscape units. The seven hectare catchment is located in the University of British Columbia Malcolm Knapp Research Forest at low elevation (190-280 masl). A weir, multiple tipping bucket rain gauges and several piezometers were used to collect hydrological data. Three separate landscape units were identified based on topography, soil properties and proximity to the stream. The units included an area of shallow slope and deep soil, a riparian area along the intermittent stream channel and an area of very shallow soil with bedrock outcrops on a steep slope. Tracers used included rhodamine-WT, uranine, sodium chloride and potassium bromide. A suite of ion selective and fluorometric probes were used along with automated water sampling to monitor tracer breakthrough. The collected samples were analysed in the lab to validate the field measurements. Tracers were dissolved in solution and applied aerially with a backpack sprayer at the onset of forecasted precipitation events to facilitate rapid infiltration into the soil. The first application took place January 4th, 2006. Measurements were then taken continuously until March 20th, 2006, when a second round of tracers was applied to the landscape units. During the first measurement period, 532 mm of precipitation fell below the forest canopy over 75 days. During the second 78 day measurement period, 290 mm of rain fell. It was found that the overall wetness of the catchment affected travel times significantly. Large storms during the first, significantly wetter, application period exhibited similar lag times from peak event discharge to tracer arrival between the different landscape units. During small precipitation events and under dryer conditions, travel times were greatest in the area of shallow slope and deep soils. These lag times are indicative of longer pathways and perhaps the non-initiation of preferential flow below certain thresholds. In general, it was concluded that delineating catchments into groups of similar landscape units based on physical characteristics may be a promising new approach to explaining catchment runoff response.

Thesis (M.S. - Watershed Management)--University of Arizona, 1984. / Includes bibliographical references (leaves 100-105).

Thesis (Ph. D. - Renewable Natural Resources)--University of Arizona. / Includes bibliographical references.