Browsing by Subject "Water budget"

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    The impact of trees on temporal variability in urban carbon and water budgets.
    (2010-07) Peters, Emily Beth
    Urbanization is responsible for some of the fastest rates of land-use change around the world, with important consequences for local, regional, and global climate. Vegetation can represent a significant proportion of many urban and suburban landscapes and modifies climate by altering local exchanges of heat, water vapor, and CO2. To assess the contribution of plant functional types to urban ecosystem processes of water loss and carbon gain in a suburban neighborhood of Minneapolis-Saint Paul, Minnesota, USA, I investigated 1) the microclimate effects of different forest types over time, 2) the relative importance of environmental and biological controls on urban tree transpiration and canopy photosynthesis, and 3) the relative importance of trees and turfgrass on the spatial and seasonal variation in suburban evapotranspiration. Regardless of plant functional type, I found that seasonal patterns of soil and surface temperature were controlled by differences in stand-level leaf area index, and that sites with high leaf area index had soil and surface temperatures 7°C and 6°C lower, respectively, than sites with low leaf area index. Plant functional type differences in canopy structure and growing season length largely explained why evergreen needleleaf trees had significantly higher annual transpiration (307 kg H2O m-2 yr-1) and canopy photosynthesis (1.02 kg C m-2 yr-1) rates per unit canopy area than deciduous broadleaf trees (153 kg H2O m-2 yr-1 and 0.38 kg C m-2 yr-1, respectively), offering an approach to scale up the tree component of urban water and carbon budgets. Turfgrass represented the largest contribution to annual evapotranspiration in recreational and residential land-use types (87% and 64%, respectively), due to a higher fractional cover and greater daily water use than trees. Component-based estimates of suburban evapotranspiration underestimated measured water vapor fluxes by 3%, providing a useful approach to predict the seasonal patterns of evapotranspiration in cities. These finding have implications for the management of urban ecosystem services related to climate, carbon sequestration, and hydrology, and for predicting the impacts of climate change on urban ecosystems.
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    Minnesota’s Water Supply: Natural Conditions and Human Impacts
    (2000) Minnesota Department of Natural Resources
    This report provides information on the State of Minnesota's water budget, human impacts, concerns in water use and protection, and strategies for water supply management. It is not specific to the Lake Superior region. From the report's conclusion: "Industry, agriculture, housing, manufacturing, power generation, and well managed public water supply are all necessary elements to nurture and sustain communities. To maintain all the natural resource features that contribute to Minnesota’s attractive quality of life, including fish and wildlife habitat and recreational opportunities, each growth and development decision needs to include consideration of its effect on the water supply and associated water resources. Careful consideration of the effect each use may have on the available water supply is essential for the sustainability of the water supply and the water supply’s ability to be recharged for future growth, development, and enjoyment."