- Title
- Land cover models to predict non-point nutrient inputs for selected biomes in South Africa
- Creator
- Slaughter, Andrew R
- Creator
- Mantel, Sukhmani K
- Subject
- To be catalogued
- Date Issued
- 2017
- Date
- 2017
- Type
- text
- Type
- report
- Identifier
- http://hdl.handle.net/10962/438152
- Identifier
- vital:73439
- Identifier
- ISBN 1816-7950
- Identifier
- https://wrcwebsite.azurewebsites.net/wp-content/uploads/mdocs/3390.pdf
- Description
- WQSAM is a practical water quality model for use in guiding southern African water quality management. However, the estimation of non-point nutrient inputs within WQSAM is uncertain, as it is achieved through a combination of calibration and expert knowledge. Non-point source loads can be correlated to particular land cover types. Although observed water quality data through which non-point source loads can be estimated are scarce, land cover databases exist covering the entire area of South Africa. To reduce the uncertainty associated with estimat-ing non-point source loads, this study describes a formal model to link the nutrient signatures of incremental flow to land cover. Study catch-ments incorporating the fynbos, grassland, savanna and thicket biomes were identified. Instream nutrients of 25 sites were modelled using WQSAM and calibrated against observed data. Multiple regression was used to investigate the relationships between the calibrated nutrient signatures of incremental flow from WQSAM and land cover within study sites. The regression models reflected greater non-point loads from cultivation-and urban-related land cover categories. The nutrient signatures of incremental flow obtained through the multiple regres-sions were consistent with those obtained through calibration of the WQSAM model at higher signature values, whereas discrepancies were evident at lower values. It is argued that this formal modelling ap-proach for linking land cover to nutrient signatures of incremental flow can be implemented for situations where it is known that there are strong non-point inputs of nutrients into a river reach. The statistical model presented in the current study could potentially be applied as an alternative to the water quality model as a relatively simple method to estimate non-point source loads of nutrients from tributary catchments in South Africa.
- Format
- 10 pages
- Format
- Publisher
- Water Research Commission
- Language
- English
- Relation
- Slaughter, A.R. and Mantel, S.K., 2017. Land cover models to predict non-point nutrient inputs for selected biomes in South Africa. Water SA, 43(3), pp.499-508
- Rights
- Publisher
- Rights
- Use of this resource is governed by the terms and conditions of the Water Research Commission Terms and Conditions of Use Statement (https://www.gov.za/terms-and-conditions-use-0)
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