John

in case that you haven't revised the URISA paper yet, I have extended the notes that I have sent you before and linked in some pictures and info. Please let me know if you would like me to continue to work on this (as you will see I got up to the section 2.4) or work on a specific section, find some references, create/modify some pictures to include into the paper, etc. I did not modify the text directly because I was not sure whether you have been working on it already

Helena

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 1. Introduction
to make it more interesting it would be good to start with the section which defines the importance of water resources and cites from the NRC publication and continue with the Challenges to GIScience from the 1st page so that the introduction will first define the problem and then define the challenges for GIS which should help to solve it

Life depends on our ability to match .....
...affect that system (National Research Council 1999)
Applications need to be multifaceted ...
....the paragraph about the new approaches to watershed management can be shortened or put under policy implications

2. Major GIScience contributions can be reorganized to improve the readability as follows:

The GIS science played a major role in the development of distributed hydrologic models and in better understanding of spatial aspects of distribution and movement of water in landscape. It has also greatly influenced the study of land use impact on water resources. The four subsections that follow illustrate some of the ways in which GIS has already been used to advance water resource management.

2.1. New GIS data, their management and delivery

Management of water resources requires a wide range of spatial data, from hydrography, representing the status of water resources, to phenomena influencing water movement and quality such as terrain, land use, soils, and climate.We should mention somewhere the urban water resources and distribution systems, I have seen some applications linking these systems with GIS but I would have to find the references

Hydrologic and water quality data - existing text can be used ( National Hydrography data set , EPA Surf your watershed, maybe add info about National wetlands inventory , as well as some state efforts, such as Texas (I need to look-up this one), Illinois ISIS

Digital Elevation Models had a profound impact on the use of GIS for water resources by stimulating the research and development of distributed hydrologic and non-point source pollution models and their linkage with GIS. Currently, new technologies, such as IFSAR ( Interferometric Synthetic Aperture Radar), LIDAR (laser), Real Time Kinetic Survey (based on mobile GPS) are bringing higher level of detail and vertical accuracy to terrain mapping (resolutions 1-2m with 15cm vertical accuracy) substantially increasing capabilties to analyze and predict movement of water in natural and anthropogenic landscapes. Radar technology was used to obtain data for the new 30m resolution global DEM as a result of recent NASA/DOD Shuttle mission, creating a potential for hydrologic studies at a global/continental scale at the level of detail currently possible only for regional studies.

For these I would have to look them up (please let me know if you need more info)
Climatic data - NEXRAD, ...
Soil data - STATSGO, SSURGO, NRCS Technical resources (includes also links to climatic, vegetation and other relevant spatial and non-spatial data)
Land cover data generated from remote sensing stimulated the study of interactions between water resources and land use. New multispectral sensors and satelite platforms, archives of digital remote sensing data from previous two decades move this study from spatial to spatio-temporal level creating a potential to better understand dynamic  landscape processes influencing water resources (e.g., impact of deforestation, urban growth)

Increasing portion of the spatial data is being distributed by Web-based GIS tools - existing text can be used here ( NSDI here, Arizona web site, EPA, NWS, etc)

It maybe also useful to mention that GIS has made the production of maps for water resources (as a means of data delivery)  much more efficient,and this is the area where probably GIS has been used the most originaly.

2.2 GIS Tools

Text from the section "New GIS Data and Tools" should go here:
Spatial interpolation: incorporation of sophisticatd methods using geostatistics (kriging), and radial basis functions (splines) provided tools for creating spatial and spatio-temporal models of climatic phenomena (precipitation..), soil properties, water quality, and DEMs from measured data.
I would keep the paragraph about Topogrid and shorten the paragraph about evaluation of accuracy of DEM (less detailed text and maybe more references including papers examining accuracy of the new DEMs from IFSARE and LIDAR and GIS tools needed to process them- please let me know if you need some) and keep interpolation of climatic data sets - maybe add more references

Watershed analysis and flowtracing: numerous algorithms for delineation of watersheds and extraction of stream networks from DEM were developed and implemented in GIS over the past decade (References e.g. from section Spatial analysis in a GIS ..) supporting efficient partition of landscapes into hydrologic units necessary for hydrologic modeling and water resource assessment.  Flow tracing has allowed to simulate the movement of water, sediment and other pollutants through landscape and better understand and identify the potential sources of non-point source pollution. Development of topographic analysis (such as methods for computation of slope, aspect and curvatures) provided basic tools for estimating parameters needed for flowrouting and hydrologic models.

Map algebra tools enabled resarchers to write simple and effective water resource models for raster data  (REFERENCES)

Network analysis ??? is this available in GIS for stream networks or urban water utilities?

Computer cartography and visualization GIS has made the production of maps for water resources much more efficient ..
text from section Improved Visualization should go here

2.3 Hydrologic modeling -

for easier reading this can be divided into

The diference between lumped and distributed models can be illustrated by a figure - I have one and I can modify it to better fit this text and I can write a little more detail about this (let me know) - see Figure.
the paragraph about the PSRM model can be shortened (it has too much technical detail for the audience) and the Corbet and Carter 1966 paper also goes probably into too much detail compared to other work mentioned in this section.
in area of integration SMS, GMS and WMS should be mentioned (developed by WES) and in area of distributed models simulating 2D flow CASC2D continuous time /continuous space modeling (Julien and his students at Colorado State) . We should also include some refrence to the MIT work (Prof Brass and his students)
On-line models should be mentioned - Purdue urban runoff, SWAT

2.4. Water resource decision support systems

3. USGIS Research challenges in water resource applications

To answer to reviewers comments I suggest merging  the following sections

3.1 Spatial data aquisition and integration + Distributed computing + Interoperability + Spatial Information Infrastructure

3.2 Extensions to Geographic Representations (object oriented efforts from ESRI+Maidment should be added) + Cognition of geographic information.
This section can be organized as folllows:
Development in representations

Development in cognition

3.3 Scale (this should have less detail and more newer material including multiscale)

3.4 Spatial Analysis and Uncertainty

here for flowrouting we have moved from geometry-based approches to physics based - this is important for flat areas, depressions, dispersal flow etc (I can write more)

3.5 GIS and society

4. Education

5. Policy (merge with GIS and society?)

6. Priority areas

7. Conclusion/summary highting most important findngs/issues

Besides other issues include here

We should also mention either in 6 or 7 the following
current trend is that GIS as a single big general system is disappearing and GIS is melting into the general computing infrastructure . We can see assimilations of GIS into end-user application rather than integrating applications into the  GIS which means that GIS will be integral part of Water resource modeling and DSS systems.

Here are links to some more figures:

Virtual Reality

Alternative figures for lumped/distributed

Lumped
average erosion for HU
Total eroded soil for HU

Distributed
Spatial distribution of erosion rates
Spatial distribution of erosion rates in a hydrologic unit 102 with the highest total eroded soil