Spatial Distribution Of Land Use Research Articles

Impacts of land use conversion on bankfull discharge and mass wasting

Mass wasting and channel incision are widespread in the Nemadji River watershed of eastern Minnesota and northwestern Wisconsin. While much of this is a natural response to glacial rebound, sediment coring and tree ring data suggest that land use has also influenced these erosional processes. We characterized land use, inventoried mass wasting, surveyed stream channels and collected discharge data along segments of five streams in the Nemadji River watershed. Due to natural relief in this region, wetlands and agricultural lands are concentrated in the flatter terrain of the uplands of the Nemadji watershed, while forestland (coniferous or deciduous) is concentrated in the deeply incised (50–200% slope) stream valleys. Bankfull discharge was higher where forests had been converted from coniferous to deciduous forests and where there were fewer wetlands. Mass wasting increased exponentially with bankfull flows. While mass wasting was not correlated with forest type conversion and agricultural land use, it was negatively dependent upon wetland extent in headwater areas. Interactions between the spatial distribution of land use and terrain obfuscate any clear cause-and-effect relationships between land use, hydrology and fluvial processes.

Land-use adjustment with a modified soil loss evaluation method supported by GIS

Land-use structure information is of significance in evaluation of soil loss owing to the contributions of various land-use patterns with different relative importance to soil and water conservation. In previous studies, a land-use structure characteristic index ( SI), defined as the sum of products between each weighted land-use type and the percentage of the impacted area in the whole test region, was proposed to reflect the resulting impacts of human factors and serve as an indirect measure of soil loss variation. In this paper, the SI was modified with consideration of spatial distribution of land-use in terms of the minimal distance between a specific land patch and a river, either the main stem or one of the primary tributaries. A topographic factor was also introduced to correct the SI. Soil loss was evaluated with support of GIS through a case study at Zhifanggou, a small catchment in the Yanhe watershed in the middle part of the Loess plateau. Comparison was made between the soil losses before and after the adjustment of land-use types since 1987 according to the governmental ordinance aiming at ecological rehabilitation. It was found that the land-use adjustment in the last 12 years has been in a right direction toward minimizing soil loss, but the difference of the actual SI in 1999 and the predicted SI corresponding to the potential optimal land-use structure implies that more efforts should be made in land-use conversion in the coming years.

Modeling and Spatially Distributing Forest Net Primary Production at the Regional Scale

Forest, agricultural, rangeland, wetland, and urban landscapes have different rates of carbon sequestration and total carbon sequestration potential under alternative management options. Changes in the proportion and spatial distribution of land use could enhance or degrade that area’s ability to sequester carbon in terrestrial ecosystems. As the ecosystems within a landscape change due to natural or anthropogenic processes, they may go from being a carbon sink to a carbon source or vice versa. Satellite image analysis has been tested for timely and accurate measurement of spatially explicit land use change and is well suited for use in inventory and monitoring of terrestrial carbon. The coupling of Landsat Thematic Mapper (TM) data with a physiologically based forest productivity model (PnET-II) and historic climatic data provides an opportunity to enhance field plot-based forest inventory and monitoring methodologies. We use periodic forest inventory data from the U.S. Department of Agriculture (USDA) Forest Service’s Forest Inventory and Analysis (FIA) Program to obtain estimates of forest area and type and to generate estimates of carbon storage for evergreen, deciduous, and mixed-forest classes. The area information is used in an accuracy assessment of remotely sensed forest cover at the regional scale. The map display of modeled net primary production (NPP) shows a range of forest carbon storage potentials and their spatial relationship to other landscape features across the southern United States. This methodology addresses the potential for measuring and projecting forest carbon sequestration in the terrestrial biosphere of the southern United States.

Assessing atrazine pollution potential to a drinking water reservoir using remote sensing and geographic information system modeling

Abstract Water quality monitoring by the City of Dallas, Texas (US) and the Institute of Applied Science, University of North Texas, has recently shown elevated atrazine concentrations in the watershed of a large drinking water reservoir in the Dallas-Fort Worth metropolitan area serving over 3,000,000 people. Atrazine is under investigation by numerous researchers as an environmental estrogen that may be involved in increasing breast cancer incidence in humans and impacting health and reproductive systems in wildlife. Since treatment technologies for atrazine removal from finished drinking water can be expensive and provide no protection to aquatic ecosystem health, watershed managers are currently seeking proactive methods to reduce the amount of atrazine entering water supply systems. The most viable approach for reducing atrazine in a drinking water reservoir begins with understanding the distribution and extent of landuse in the watershed where atrazine may be applied. Understanding the spatial distribution of areas potentially contributing atrazine runoff facilitates developing an effective atrazine reduction program of the best management practices that are appropriate to a particular region. Using remotely sensed satellite imagery and geographic information system modeling, an analysis of the spatial distribution of landuse, soil erodibility, and surface slope information in a large watershed in north central Texas was conducted. An ‘atrazine pollution potential’ model was developed and applied to over 224,000 hectares draining into Lake Lewisville which provides drinking water to Dallas and surrounding communities. Model results compared well with in situ water quality measurements of atrazine, and point to areas most in need of best management practice implementation.

Interpreting Land-Use History by Integrating Aerial Photographs, Near-Surface Geophysics, and Field Observations Into a Digital Database

Near-surface, non-invasive field geophysics was used to investigate the land-use history of a 60-aere former industrial site in Lancaster, Pennsylvania. A proton-precession magnetometer and a Geonics EM31 non-contacting electromagnetic conductivity meter were used to measure eleven profiles across the site. Based on all the available data, four major land-use areas are distinguished: building foundation areas, excavated areas (clay mining), landfills and background areas. The geophysical data show distinct signatures for these land-use classifications. The conductivity readings can be characterized by their median values and standard deviations within each of these classifications: a) sports fields (background), 7.5 ±2.8 millisiemens per meter (mS/m); b) excavated areas, 4.6 ±3.4 mS/m; c) building foundations, 7.7 ±4.0 mS/m; and d) landfill areas: 34.0 ±30.8 mS/m. For magnetics, the median (with background subtracted) and standard deviation within each classifications are: 1) sports fields (background), −0.9 ±8.7 nanoteslas (nT); 2) excavated areas, −0.8 ±10.8 nT; 3) building foundations, −96.2 ±291.0 nT; 4) landfill areas, 37.7 ±473.9 nT. Both conductivity and magnetics show similar patterns, although conductivity provides clearer visual discrimination between land-use types. The in-phase conductivity data are consistent with the land-use patterns determined from the aerial photographs and the other geophysical data. Zero (negative) readings occur over areas with high metal content such as the buildings foundations area and the landfill area. Clay pit areas show uniformily low readings consistent with the lack of metallic objects in these areas. All the data, including historical aerial photographs, historical land-cover information, geophysical data, topography, hydrology, and existing buildings and infrastructure were integrated into a digital database. Data such as historical aerial photographs provided temporal (past) information about the land-use history of the site, while the geophysical data provided current information about the type and spatial distribution of land use. The integration of the geophysical data with other data in a digital database is an effective tool for interpreting land-use history and understanding present environmental conditions

Study on the Spatial Distribution of Land Use and Population in Metro Manila

The population of Metro Manila has increasing from 5, 926 thousand in 1980 to 9, 454thousand in 1995 because of migration from local regions. Now increase of population causes expansion of squatter and slum area and will cause more serious environmental problems. Upon reviewing previous urban model for predictingthe population increasing impact of the change of land use, authors shows that most of the notable models did not pay due attention to the lack of data in developing countries. Then, this research is analyzing the spatial distribution of land use and population, using a land use data of Metro Manila in 1986 and 1996.

APPLICATION OF GIS FOR MANAGEMENT AND PLANNING OF SEWERAGE IN A SMALL URBAN AREA

The development of geographic information system (GIS) has significantly changed the way we acquire and use spatial data and introduced the potential for increasing the use for planning drainage and determining the physical watershed characteristics in hydrologic modeling.In this paper, we describe the attempts that further incorporates the spatial analysis capabilities of GIS into the sewerage management and planning. We construct a distributed model in which the spatial distribution of landuse is taken into consideration and propose a new index for the danger of inundation of each sewerage pipe that is acquired by the difference between the distributed and lumped models.

Application of Terrain Analysis and Geographic Information Systems to the Construction of Hydrologic Databases: A Case Study

Spatial data in digital form have become increasingly available in a wide range of different formats. Often, however, the available data are unreliable even in routine applications. This paper illustrates these problems in relation to both digital elevation and stream network data. It presents new techniques within the framework of Geographic Information Systems (GIS) for the Great Miami River Basin of Ohio and Indiana to improve data usability. Inconsistencies in the digital elevation models (DEMs) were reduced by combing the raw 1-degree DEMs with hydrography layers to create a new, hydrologically correct DEM. Relevant topographic characteristics of 34 gaged watersheds could be extracted with improved accuracy from the modified DEM. Discrepancies in the drainage density in the hydrography layers were reduced by extracting the stream network from the DEM. The result is a consistent drainage network that eliminates inconsistencies inherent in the original data across the Indiana-Ohio state line. The database also includes the spatial distribution of land use and land cover, and soil properties. This study shows that computer processing can improve the consistency of commercial data products.

Colonist Land‐Allocation Decisions, Land Use, and Deforestation in the Ecuadorian Amazon Frontier

As one of the last agricultural frontiers of the humid tropics, Amazonia is the largest area of the world currently undergoing frontier settlement. Although the earliest intrusions of foreign populations into Amazonia date from pre-Hispanic times, the large-scale entrance of peasant colonists into the vast region is a recent phenomenon. Much of this movement represents the spontaneous migration of peoples, but governments in the region have also become increasingly interested in opening up and integrating Amazonia to national and international economies. These actions are frequently seen as potential solutions to a number of national problems, including the need to increase agricultural production, correct spatial imbalances in the distribution of population, exploit frontier lands for reasons of national security, and defuse potentially serious political problems resulting from the existing agrarian structure, landlessness, and unemployment. The upper basin of the Amazon in Ecuador, bordering on the eastern slopes of the Andes, is one such area of frontier settlement. Recent decades have witnessed the rapid conversion of these Amazonian forests to agricultural uses through a series of schemes bearing such labels as land development and colonization. Most forest intervention in the region has come at the hands of colonist farmers attempting to establish land claims along transport routes originally constructed to aid in petroleum exploration and exploitation. These are farmers who formerly have made a living in long-established farmlands and who, for various reasons (population pressures, pervasive poverty, maldistribution of farmland, lack of inputs for intensive cultivation, lack of nonagrarian livelihood opportunities, and generally inadequate rural development) have been increasingly squeezed out of their homelands. A marginal person by virtue of his low socioeconomic and political status, the farmer often perceives

Water Balance, Climate Change and Land-use Planning in the Pearl Harbor Basin, Hawai'i

The Pearl Harbor basin on the tropical oceanic island of O'ahu, Hawaii, exhibits extreme climatic gradients, rapid land-use change and groundwater use near sustainable yield. The basin's water usage and groundwater recharge, and hence water yield, are strongly influenced by the spatial distribution of land use. Current recharge is expected to drop by about one-eighth with the demise of the remaining sugar-cane and pineapple. Evidence suggests that lower rainfall and increased evaporation may well accompany warmer periods in Hawaii, and water-balance simulations indicate many scenarios having a significant decrease in available water. Land-use planners can use such results in tandem with multiobjective optimization models to generate alternative land-use plans and show trade-offs among objectives.