Value of river discharge data for global-scale hydrological modeling

Hunger, Martin; Döll, Petra

doi:10.5194/hessd-4-4125-2007

Cited by 43 publications

(52 citation statements)

References 27 publications

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“…In most macro-scale river routing models (e.g., Miller et al, 1996;Arora and Boer, 2002;Oki et al, 1999;Hunger and Döll, 2008), the amount of water discharged from each grid is calculated and transferred to the downstream grid prescribed by the river network map. Within this model framework, the traditional D8 form is a sufficient, but not necessary, condition for describing the river network map.…”

Section: Resultsmentioning

confidence: 99%

Deriving a global river network map and its sub-grid topographic characteristics from a fine-resolution flow direction map

Yamazaki

Oki

Kanae

2009

Hydrol. Earth Syst. Sci.

131

132

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Abstract. This paper proposes an improved method for converting a fine-resolution flow direction map into a coarseresolution river network map for use in global river routing models. The proposed method attempts to preserve the river network structure of an original fine-resolution map in the upscaling procedure, as this has not been achieved with previous upscaling methods. We describe an improved method in which a downstream cell can be flexibly located on any cell in the river network map. The improved method preserves the river network structure of the original flow direction map and allows automated construction of river network maps at any resolution. Automated construction of a river network map is helpful for attaching sub-grid topographic information, such as realistic river meanderings and drainage boundaries, onto the upscaled river network map. The advantages of the proposed method are expected to enhance the ability of global river routing models by providing ways to more precisely represent surface water storage and movement.

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Section: Resultsmentioning

confidence: 99%

Deriving a global river network map and its sub-grid topographic characteristics from a fine-resolution flow direction map

Yamazaki

Oki

Kanae

2009

Hydrol. Earth Syst. Sci.

131

132

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“…In fact, half of all cities with populations greater than 100,000 are located in water-scarce basins. In these basins, agricultural water consumption accounts for more than 90 % of all freshwater depletions (Hunger and Döll 2008;Richter et al 2013). In a critical analysis, Richter et al (2013) point out that nearly all water used for domestic and industrial purposes is eventually returned to a water body.…”

Section: Water Challenges In the Citymentioning

confidence: 99%

The challenges of water, waste and climate change in cities

Koop

Leeuwen

2016

Environ Dev Sustain

329

157

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Cities play a prominent role in our economic development as more than 80 % of the gross world product (GWP) comes from cities. Only 600 urban areas with just 20 % of the world population generate 60 % of the GWP. Rapid urbanization, climate change, inadequate maintenance of water and wastewater infrastructures and poor solid waste management may lead to flooding, water scarcity, water pollution, adverse health effects and rehabilitation costs that may overwhelm the resilience of cities. These megatrends pose urgent challenges in cities as the cost of inaction is high. We present an overview about population growth, urbanization, water, waste, climate change, water governance and transitions. Against this background, we discuss the categorization of cities based on our baseline assessments, i.e. our City Blueprint research on 45 municipalities and regions predominantly in Europe. With this bias towards Europe in mind, the challenges can be discussed globally by clustering cities into distinct categories of sustainability and by providing additional data and information from global regions. We distinguish five categories of sustainability: (1) cities lacking basic water services, (2) wasteful cities, (3) water-efficient cities, (4) resource-efficient and adaptive cities and (5) water-wise cities. Many cities in Western Europe belong to categories 3 and 4. Some cities in Eastern Europe and the few cities we have assessed in Latin America, Asia and Africa can be categorized as cities lacking basic water services. Lack of water infrastructures or obsolete infrastructures, solid waste management and climate adaptation are priorities. It is concluded that cities require a long-term framing of their sectoral challenges into a proactive and coherent Urban Agenda to maximize the co-benefits of adaptation and to minimize the cost. Furthermore, regional platforms of cities are needed to enhance city-to-city learning and to improve governance capacities necessary to accelerate effective and efficient transitions towards water-wise cities. These learning alliances are needed as the time window to solve the global water governance crisis is narrow and rapidly closing. The water sector can play an important role but needs to reframe and refocus radically.

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“…For discharge estimates obtained solely from repeated Landsat TM measurements of instantaneous river surface width (Fig. 3), the mean reach-averaged discharge root-mean-square error (RMSE) is 2,585 m 3 Fig. 3.…”

Section: Feasibility Demonstrations and Implications For Global Watermentioning

confidence: 99%

“…For much of the world, river gauge measurements are rare, nonexistent, or proprietary. Even wellmonitored countries have sparsely distributed networks, thus limiting current understanding of water losses along river courses, habitat changes, and flood risk (3,4). Satellites, in contrast, provide spatially dense coverage globally, attracting calls for a global river discharge mapping capacity from space (5)(6)(7)(8)(9)(10).…”

mentioning

confidence: 99%

Toward global mapping of river discharge using satellite images and at-many-stations hydraulic geometry

Gleason

Smith

2014

Proc. Natl. Acad. Sci. U.S.A.

285

288

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Rivers provide critical water supply for many human societies and ecosystems, yet global knowledge of their flow rates is poor. We show that useful estimates of absolute river discharge (in cubic meters per second) may be derived solely from satellite images, with no ground-based or a priori information whatsoever. The approach works owing to discovery of a characteristic scaling law uniquely fundamental to natural rivers, here termed a river's at-many-stations hydraulic geometry. A first demonstration using Landsat Thematic Mapper images over three rivers in the United States, Canada, and China yields absolute discharges agreeing to within 20-30% of traditional in situ gauging station measurements and good tracking of flow changes over time. Within such accuracies, the door appears open for quantifying river resources globally with repeat imaging, both retroactively and henceforth into the future, with strong implications for water resource management, food security, ecosystem studies, flood forecasting, and geopolitics. S ome 80% of the world's population and 65% of its river ecosystems are threatened by insecure water supply, yet global knowledge of the river discharges upon which these depend is surprisingly poor (1, 2). For much of the world, river gauge measurements are rare, nonexistent, or proprietary. Even wellmonitored countries have sparsely distributed networks, thus limiting current understanding of water losses along river courses, habitat changes, and flood risk (3, 4). Satellites, in contrast, provide spatially dense coverage globally, attracting calls for a global river discharge mapping capacity from space (5-10). However, previous efforts to estimate river discharge from remotely sensed observations have all required inclusion of some form of ancillary ground-based information, such as gauge measurements, bathymetric surveys, and/or calibrated hydrology models that are simply unavailable for most of the planet (11-18). To remove this dependence on ground-based information, we show that useful estimates of absolute river discharge (i.e., in units of cubic meters per second) may be derived solely from multiple satellite images of a river, with no ground-based or a priori information whatsoever, through use of a characteristic scaling law, here termed a river's atmany-stations hydraulic geometry (AMHG). As will be shown in this paper, AMHG effectively halves the number of parameters required by traditional hydraulic geometry, thus paving the way for remote estimation of a single remaining parameter-and thus river discharge-through repeated satellite image observations along a river course. The presence of AMHG is verified in 12 of 12 rivers examined, using 88 in situ gauging stations, three fieldcalibrated hydrodynamic models incorporating 772 field-surveyed bathymetric cross-sections, and 42 Landsat Thematic Mapper (TM) satellite images (SI Text, section S1, Materials and Methods and Tables S1 and S2). Following a description of width AMHG, an innovative satellite discharge estimation approach i...

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Value of river discharge data for global-scale hydrological modeling

Cited by 43 publications

References 27 publications

Deriving a global river network map and its sub-grid topographic characteristics from a fine-resolution flow direction map

Deriving a global river network map and its sub-grid topographic characteristics from a fine-resolution flow direction map

The challenges of water, waste and climate change in cities

Toward global mapping of river discharge using satellite images and at-many-stations hydraulic geometry

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