The Effect of Farm Dams and Constructed Banks on Hydrologic Connectivity and Runoff Estimation in Agricultural Landscapes

Environmental Modelling & Software, Volume 24, Issue 8, August 2009, Pages 959-968

J.N. Callow and K.R.J. Smettem

“System coupling and landscape connectivity control the flow of water and sediment through landscapes. Although coupling is well known to control long-term landscape development and shorter-term sensitivity to disturbance, the anthropogenic influences on coupling are seldom considered in hydrologic investigations. In particular, the building of small-scale water diversion (earth banks) and collection (farm dams) infrastructure on hillslopes in dryland agricultural areas may significantly alter hillslope–channel coupling. Twelve sub-catchment basins in a dryland agricultural region were investigated under their natural (ignoring infrastructure) and modified (including infrastructure) conditions to investigate the influence of water collection infrastructure on hydrologic connectivity, and whether manual modification of a Digital Elevation Model (DEM) could account for the impact of these factors in hydrologic simulation of hydrologic and geomorphic processes.

“Dam numbers and density have both increased over the period of available aerial photography (1965–1999), resulting in an average 39.5% reduction (range 4.3–86.7%) in the area retaining hydrologic connectivity with the basin outlet. Analysis of basins dominated by either banks or dams, and with combinations of both was performed using the Cumulative Area Distribution (CAD), Hypsometric Curve (HC), Simplified Width Function (SWF) and Instantaneous Unit Hydrograph (IUH). The geomorphic descriptors (CAD and HC) showed little change in basin structure as a result of farm dam and bank construction, but hydrologic descriptors (SWF and IUH) indicate that hillslope processes are significantly altered by farm dams and banks. Because runoff models are sensitive to catchment area, incorporating hillslope water capture and diversion infrastructure into the base data sets may offer a solution to improved parameterisation of spatial models of hydrology, particularly in dryland agricultural regions.”

Spatial Patterns and Health Disparities in Pediatric Lead Exposure in Chicago: Characteristics and Profiles of High-Risk Neighborhoods

The Professional Geographer, Volume 62, Issue 1 February 2010 , pages 46 – 65

Tonny J. Oyana; Florence M. Margai

“Lead poisoning remains a major environmental health threat and a persistent source of health disparities in the United States. In this retrospective study, statistical and geospatial approaches were used to evaluate age- and gender-specific differences in childhood lead prevalence across Chicago, assess the spatiotemporal dynamics of the disease, and identify the socioeconomic and racial composition of high-risk communities. Elevated blood lead levels (≥ 10 μ g/dL of lead) decreased significantly during the study period but disparities persisted across neighborhoods. A significant association was observed between high-risk neighborhoods and housing age, low income, and minority populations. These findings provide insights into the complex geographies of lead exposure and could serve as a basis for developing more targeted health intervention programs. ”