Comparison of the water balance for an undeveloped and a suburban catchment

Stephenson, David

doi:10.1080/02626669409492751

Cited by 28 publications

(24 citation statements)

References 5 publications

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“…For example, in Vancouver, British Columbia, lawn irrigation increased evapotranspiration on a 0.21 km 2 suburban area with 40 % impervious cover (Grimmond and Oke 1986). Similar results were observed in a separate study conducted on a 0.75 km 2 suburban catchment with 25 % impervious area in Johannesburg, South Africa (Stephenson 1994). However, further research is required to confirm the applicability of these observations in other urban catchments in water-scarce regions such as SSA.…”

Section: Evapotranspirationsupporting

confidence: 83%

“…The study further demonstrated that evapotranspiration declined by about 220 mm per year in a catchment with 100 % urbanization. However, on relatively small catchments (<1.0 km 2 ), urbanization has been observed to increase evapotranspiration (Stephenson 1994;Grimmond and Oke 1999). For example, in Vancouver, British Columbia, lawn irrigation increased evapotranspiration on a 0.21 km 2 suburban area with 40 % impervious cover (Grimmond and Oke 1986).…”

Section: Evapotranspirationmentioning

confidence: 98%

“…This is partly due to multiple counteracting processes including increased atmospheric water demand induced by urban heat island, reduced soil moisture storage due to impervious surfaces, and increased water availability through landscape irrigation. Accordingly, the few available studies indicate that the effects of urbanization on evapotranspiration are complex and inconsistent (Stephenson 1994;Grimmond and Oke 1999;O'Driscoll et al 2010). To elucidate the impacts of urban roof water harvesting systems on evapotranspiration, it is important to focus on the individual processes that constitute evapotranspiration: interception, bare soil evaporation and transpiration.…”

Section: Evapotranspirationmentioning

confidence: 99%

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Hydrological Impacts of Urbanization and Urban Roof Water Harvesting in Water-limited Catchments: A Review

Gwenzi

Nyamadzawo

2014

Environ. Process.

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Roof water harvesting is a potential source of water for domestic and livelihood uses in water-scarce urban areas of the world such as sub-Saharan Africa (SSA). However, little is known about the hydrological impacts of incorporating roof water harvesting on on-site and downstream hydrology of urbanized catchments. Therefore, the current review investigates the effects of urbanization and urban roof water harvesting on hydrological processes, rainfall-runoff relationships, groundwater recharge and water contamination, and highlights future research directions. The review showed that the urban heat island effect increases the frequency and magnitude of convective storms. The high proportion and connectivity of impervious surfaces reduce infiltration, thereby increasing the runoff coefficient and Hortonian runoff. Urbanization reduces the minimum threshold rainfall for runoff generation, resulting in multi-peak hydrographs reflecting the contribution of both pervious and impervious surfaces. Urban roof water harvesting increases catchment lag time, but reduces downstream peak and total discharge, baseflow and flow velocity. Utility trenches, tunnels and buried structures form a complex network resembling a shallow urban karst system, which provides preferential flow pathways for groundwater recharge by imported water via leakages. Contrary to the widely held notion that urbanization reduces groundwater recharge by increasing impervious surfaces, empirical evidence shows significant urban-enhanced recharge in water-limited urban catchments. However, we contend that excessive groundwater abstraction for multiple uses in water-scarce regions offsets the urban-enhanced recharge, resulting in groundwater depletion. Due to the overriding collective effects of reduced soil moisture and vegetation cover on evapotranspiration in water-limited environments, we conclude that urbanization lowers evapotranspiration. Urban roof water harvesting short-cuts the urban water cycle, thereby minimizing the risk of runoff contamination that could occur during its extended flow over contaminated land surfaces. Contaminated sources of recharge, such as wastewater leakages coupled with the urban karst system, promote groundwater pollution. Overall, urban roof water harvesting imparts additional Zimbabwe complexity to urban catchments, and has potentially adverse effects on ecohydrology. Understanding these impacts is critical for planning, designing and operation of urban roof water harvesting systems. Future research may provide a comprehensive understanding of these impacts by combining hydrological measurements and process modelling in urbanized catchments incorporating roof water harvesting.

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Section: Evapotranspirationsupporting

confidence: 83%

Section: Evapotranspirationmentioning

confidence: 98%

Section: Evapotranspirationmentioning

confidence: 99%

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Hydrological Impacts of Urbanization and Urban Roof Water Harvesting in Water-limited Catchments: A Review

Gwenzi

Nyamadzawo

2014

Environ. Process.

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“…Typical water balances focus on evaluating the impact of urbanization on the hydrologic system, the provision of traditional water servicing and investigation of attenuation strategies (Stephenson 1994;Grimmond and Oke 1986;Binder et al 1997). The applied methods vary; although the majority involve an accounting of input and output based on average annual or monthly spreadsheet calculations.…”

Section: Discussionmentioning

confidence: 99%

Total Urban Water Cycle Models in Semiarid Environments—Quantitative Scenario Analysis at the Area of San Luis Potosi, Mexico

Martínez

Escolero

Wolf

2010

Water Resour Manage

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Systems view thinking and holistic urban water cycle concepts are increasingly called upon for integrated analysis of urban water systems to mitigate water stress in large urban agglomerations. However, integrated analysis is frequently not applied due to the inherent complexity, limitations in data availability and especially the lack of guidelines and suitable software tools. The paper presents the application of the total urban water balance model UVQ to the City of San Luis Potosi (1.2 Mio inhabitants) under the arid conditions of Northern Mexico. UVQ is a lumped parameter model which describes water and contaminant flows from source to sink in urban areas and includes all water types such as rainwater, imported water, surface runoff, wastewater and groundwater. The results were especially useful for spatially explicit groundwater recharge calculation in urban areas. A range of urban water scenarios, including different supply strategies and the effect of externalities such as demand change, were simulated and compared to a calibrated baseline scenario. The analysis demonstrated that shallow urban groundwater resources can substantially mitigate problems of water scarcity and overexploitation of deep aquifers if appropriate water quality protection or fit-for-use paradigms are put into place. The modelling exercise delivers relevant information for the decision 240 S.E. Martinez et al. making process and identifies the most relevant shortcomings in current monitoring systems. This represents a key step on the path to water sensitive and sustainable urban development, including the urban aquifers which have been neglected in the management policy of most cities of the Mexican arid zone.

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“…In general, it is possible to say that significant flow regulation leads to a change in FDCs shape, which becomes flatter respect to the natural case, with an attenuation of higher flows (floods) and an increase of low flows [17]. Leopold, in 1968 [18], and Stephenson, in 1994 [19] group in three main categories the impacts on river flow due to anthropic activities: 1) effect on the long-term water balance at the catchment scale (long-term variability); 2) variation from year to year of the statistics of river flow (inter-annual variability); 3) intraannual variation of river flow.…”

Section: Anthropization Effects On River Flow Regimementioning

confidence: 99%

Uncertainties in Flow Duration Curves in anthropized catchments

Dresti

2015

Ravage of the Planet IV

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Flow Duration Curves (FDC) are a traditional tool in water resources management. Their applications range from environmental protection planning to hydrosystems design. In many problems natural FDC are needed, that is curves referring to river regimes before alterations due to anthropic water uses.Estimation of FDC, as known, is uncertain in ungauged catchments. Also in gauged catchments, however, uncertainty may be relevant if available flow data are few or recorded after the anthropic alterations were set. This uncertainty may be high in mountain rivers, whose regime is typically more irregular and with significant alterations, mostly due to withdrawals for hydropower uses.The scope of this paper is to analyze these uncertainties, using a methodology to link anthropic uses to FDC alterations. Application to a catchment in the southwestern Alps is finally presented.

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Comparison of the water balance for an undeveloped and a suburban catchment

Cited by 28 publications

References 5 publications

Hydrological Impacts of Urbanization and Urban Roof Water Harvesting in Water-limited Catchments: A Review

Hydrological Impacts of Urbanization and Urban Roof Water Harvesting in Water-limited Catchments: A Review

Total Urban Water Cycle Models in Semiarid Environments—Quantitative Scenario Analysis at the Area of San Luis Potosi, Mexico

Uncertainties in Flow Duration Curves in anthropized catchments

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