ABSTRACT:

Surface water in arid regions is essential to many organisms including large mammals of conservation concern. For many regions little is known about the extent, ecology and hydrology of ephemeral waters, because they are challenging to map given their ephemeral nature and small sizes. Our goal was to advance surface water knowledge by mapping and monitoring ephemeral water from the wet to dry seasons across the Kavango-Zambezi (KAZA) transfrontier conservation area of southern Africa (300,000 km2). We mapped individual waterholes for six time points each year from mid-2017 to mid-2020, and described their presence, extent, duration, variability, and recurrence. We further analyzed a wide range of physical and landscape aspects of waterhole locations, including soils, geology, and topography, to climate and soil moisture. We identified 2.1 million previously unmapped ephemeral waterholes (85-89% accuracy) that seasonally extend across 23.5% of the study area. We confirmed a distinct ‘blue wave’ with ephemeral water across the region peaking at the end of the rainy season. We observed a wide range of waterhole types and sizes, with large variances in seasonal and interannual hydrology. We found that ephemeral surface water spatiotemporal patterns were was associated with soil type; loam soils were most likely to hold water for longer periods in the study area. From the wettest time period to the driest, there was a ~44,000 km2 (62%) decrease in ephemeral water extent across the region—these dramatic seasonal fluctuations have implications for wildlife movement. A warmer and drier climate, expected human population growth, and associated agricultural expansion and development may threaten these sensitive and highly variable water resources and the wildlife that depend on them.

This resource contains a map of surface water frequency observed 2017-2020.

ABSTRACT:

Surface water in arid regions is essential to many organisms including large mammals of conservation concern. For many regions little is known about the extent, ecology and hydrology of ephemeral waters, because they are challenging to map given their ephemeral nature and small sizes. Our goal was to advance surface water knowledge by mapping and monitoring ephemeral water from the wet to dry seasons across the Kavango-Zambezi (KAZA) transfrontier conservation area of southern Africa (300,000 km2). We mapped individual waterholes for six time points each year from mid-2017 to mid-2020, and described their presence, extent, duration, variability, and recurrence. We further analyzed a wide range of physical and landscape aspects of waterhole locations, including soils, geology, and topography, to climate and soil moisture. We identified 2.1 million previously unmapped ephemeral waterholes (85-89% accuracy) that seasonally extend across 23.5% of the study area. We confirmed a distinct ‘blue wave’ with ephemeral water across the region peaking at the end of the rainy season. We observed a wide range of waterhole types and sizes, with large variances in seasonal and interannual hydrology. We found that ephemeral surface water spatiotemporal patterns were was associated with soil type; loam soils were most likely to hold water for longer periods in the study area. From the wettest time period to the driest, there was a ~44,000 km2 (62%) decrease in ephemeral water extent across the region—these dramatic seasonal fluctuations have implications for wildlife movement. A warmer and drier climate, expected human population growth, and associated agricultural expansion and development may threaten these sensitive and highly variable water resources and the wildlife that depend on them.

ABSTRACT:

Surface water in arid regions is essential to many organisms including large mammals of conservation concern. For many regions little is known about the extent, ecology and hydrology of ephemeral waters, because they are challenging to map given their ephemeral nature and small sizes. Our goal was to advance surface water knowledge by mapping and monitoring ephemeral water from the wet to dry seasons across the Kavango-Zambezi (KAZA) transfrontier conservation area of southern Africa (300,000 km2). We mapped individual waterholes for six time points each year from mid-2017 to mid-2020, and described their presence, extent, duration, variability, and recurrence. We further analyzed a wide range of physical and landscape aspects of waterhole locations, including soils, geology, and topography, to climate and soil moisture. We identified 2.1 million previously unmapped ephemeral waterholes (85-89% accuracy) that seasonally extend across 23.5% of the study area. We confirmed a distinct ‘blue wave’ with ephemeral water across the region peaking at the end of the rainy season. We observed a wide range of waterhole types and sizes, with large variances in seasonal and interannual hydrology. We found that ephemeral surface water spatiotemporal patterns were was associated with soil type; loam soils were most likely to hold water for longer periods in the study area. From the wettest time period to the driest, there was a ~44,000 km2 (62%) decrease in ephemeral water extent across the region—these dramatic seasonal fluctuations have implications for wildlife movement. A warmer and drier climate, expected human population growth, and associated agricultural expansion and development may threaten these sensitive and highly variable water resources and the wildlife that depend on them.

This contains Google Earth Engine code to generate water coverage data for Schaffer-Smith et al 2022.

ABSTRACT:

Surface water in arid regions is essential to many organisms including large mammals of conservation concern. For many regions little is known about the extent, ecology and hydrology of ephemeral waters, because they are challenging to map given their ephemeral nature and small sizes. Our goal was to advance surface water knowledge by mapping and monitoring ephemeral water from the wet to dry seasons across the Kavango-Zambezi (KAZA) transfrontier conservation area of southern Africa (300,000 km2). We mapped individual waterholes for six time points each year from mid-2017 to mid-2020, and described their presence, extent, duration, variability, and recurrence. We further analyzed a wide range of physical and landscape aspects of waterhole locations, including soils, geology, and topography, to climate and soil moisture. We identified 2.1 million previously unmapped ephemeral waterholes (85-89% accuracy) that seasonally extend across 23.5% of the study area. We confirmed a distinct ‘blue wave’ with ephemeral water across the region peaking at the end of the rainy season. We observed a wide range of waterhole types and sizes, with large variances in seasonal and interannual hydrology. We found that ephemeral surface water spatiotemporal patterns were was associated with soil type; loam soils were most likely to hold water for longer periods in the study area. From the wettest time period to the driest, there was a ~44,000 km2 (62%) decrease in ephemeral water extent across the region—these dramatic seasonal fluctuations have implications for wildlife movement. A warmer and drier climate, expected human population growth, and associated agricultural expansion and development may threaten these sensitive and highly variable water resources and the wildlife that depend on them.

This will contain individual time step rasters of water coverage 2017-2020.

ABSTRACT:

Surface water in arid regions is essential to many organisms including large mammals of conservation concern. For many regions little is known about the extent, ecology and hydrology of ephemeral waters, because they are challenging to map given their ephemeral nature and small sizes. Our goal was to advance surface water knowledge by mapping and monitoring ephemeral water from the wet to dry seasons across the Kavango-Zambezi (KAZA) transfrontier conservation area of southern Africa (300,000 km2). We mapped individual waterholes for six time points each year from mid-2017 to mid-2020, and described their presence, extent, duration, variability, and recurrence. We further analyzed a wide range of physical and landscape aspects of waterhole locations, including soils, geology, and topography, to climate and soil moisture. We identified 2.1 million previously unmapped ephemeral waterholes (85-89% accuracy) that seasonally extend across 23.5% of the study area. We confirmed a distinct ‘blue wave’ with ephemeral water across the region peaking at the end of the rainy season. We observed a wide range of waterhole types and sizes, with large variances in seasonal and interannual hydrology. We found that ephemeral surface water spatiotemporal patterns were was associated with soil type; loam soils were most likely to hold water for longer periods in the study area. From the wettest time period to the driest, there was a ~44,000 km2 (62%) decrease in ephemeral water extent across the region—these dramatic seasonal fluctuations have implications for wildlife movement. A warmer and drier climate, expected human population growth, and associated agricultural expansion and development may threaten these sensitive and highly variable water resources and the wildlife that depend on them.

This resource contains a raster of maximum wetness extent observed 2017-2020.

ABSTRACT:

This resource contains supporting data for the publication "Landscape pollution source dynamics highlight priority locations for basin-scale interventions to protect water quality under hydroclimatic variability".

A Cape Fear River Basin Water Quantity and Quality Soil and Water Assessment Tool Model (CFRB WQQ SWAT Model) was developed to examine risks to water quality from point and non-point sources under current land use and weather conditions from 1982-2019, and to facilitate the evaluation of scenarios, including watershed-scale restoration of forests and wetlands. This work built on a Cape Fear River Basin Water Quantity Model developed by USGS for a Coastal Carolinas Focus Area Study of water availability and water use.

Datasets contained in this resource include:
-Spatial data delineating the basin, the CFRB WQQ SWAT Model subbasins, and the CFRB SWAT Model reach network.
-Predicted daily streamflow and loads of sediment, total nitrogen and total phosphorus based on the SWAT simulation reach and reservoir outputs.
-Predicted runoff and loads of sediment, total nitrogen and total phosphorus based on the SWAT simulation subbasin output.