JOURNAL OF THE AMERICAN WATER RESOURCES ASSOCIATION AMERICAN WATER RESOURCES ASSOCIATION OPEN WATER DATA IN SPACE AND TIME1 David R. Maidment2 ABSTRACT: An Open Water Data Initiative has been established by the federal government to enhance water information sharing across the United States (U.S.) using standardized web services for geospatial and temporal data. In a parallel effort, the National Weather Service has established a new National Water Center on the Tuscaloosa campus of the University of Alabama, at which a new National Water Model starts operations in June 2016, to continually simulate and forecast streamflow discharge throughout the continental U.S. These two developments support the interoperability of streamflow and hydrologic information in time and space from modeled and observed sources through the use of open standards to share water information. (KEY TERMS: data management; geospatial analysis; monitoring; web services; water data.) Maidment, David R., 2016. Open Water Data in Space and Time. Journal of the American Water Resources Asso- ciation (JAWRA) 1-9. DOI: 10.1111/1752-1688.12436 INTRODUCTION Alabama, which was formally opened in May 2015. The aim of this Center is to “improve water resource forecasts, understand how water moves across the Several events occurring during the spring and land and rivers, and facilitate creative and informed summer of 2014 spurred the establishment of an decisions — all utilizing the best available science” Open Water Data Initiative in the United States (http://www.nws.noaa.gov/oh/nwc/, accessed August 6, (U.S.). In March 2014, President Obama launched a 2015). The National Water Center is intended to sup- Climate Data Initiative and invited leaders of high port the combined efforts of federal water agencies technology firms and representatives of community working together in the Integrated Water Resources organizations to the White House to explore how Science and Services partnership, whose founding information from the climate data holdings of the fed- members were the U.S. Army Corps of Engineers, eral government could be made more accessible to cit- U.S. Geological Survey (USGS), and NWS, joined in izens so that they could better adapt to climate the summer of 2015 by the Federal Emergency Man- change, especially with respect to the effects of sea agement Agency. level rise. This event was part of a larger emphasis The first two goals of this Center are an “opera- on Open Data in the federal government and tions center with situation rooms” to develop a com- prompted the question: what could be achieved by an mon operating picture of water conditions from floods Open Water Data initiative? to droughts, and a “geo-intelligence laboratory” to In May 2014, a new National Water Center was support the effort with state-of-the-science enterprise established by the National Weather Service (NWS) GIS information (http://www.nws.noaa.gov/oh/nwc/, on the Tuscaloosa campus of the University of accessed August 6, 2015). A National Water Model is 1Paper No. JAWRA-15-0123-P of the Journal of the American Water Resources Association (JAWRA). Received August 7, 2015; accepted April 20, 2016. © 2016 American Water Resources Association. Discussions are open until six months from issue publication. 2Hussein M. Alharthy Centennial Chair in Civil Engineering, University of Texas, Austin, Texas 78712 (E-Mail/Maidment: [email protected]). JOURNAL OF THE AMERICAN WATER RESOURCES ASSOCIATION 1 JAWRA MAIDMENT starting operations in June 2016, which will continu- some of the elements of an Open Water Data Initia- ally simulate and forecast land surface hydrology and tive might consist, and to examine whether there streamflow discharge across the continental U.S. This might be developed a National Water Data Infras- requires an underpinning foundation of continually tructure with similar goals for water to those that updated geospatial and temporal information about the NSDI embodies for geospatial information to water conditions throughout the nation. underlie the operation of the National Water Model. The Open Water Data Initiative was launched dur- ing the summer of 2014 by Anne Castle, then Assis- tant Secretary for Water and Science of the Department of the Interior, in her capacity as Chair WATER DATA IN SPACE of the Federal Geographic Data Committee and of the Advisory Committee on Water Information, the two bodies within the federal government which coordi- The geographic information encapsulated in the nate national geographic and water information, NSDI is divided into a set of themes describing infor- respectively. The Initiative is coordinated through a mation of particular kinds, divided into core and sup- Subcommittee on Spatial Water Data, which serves plemental framework themes. The two Core to represent water within the Federal Geographic Framework Themes relevant for water are Hydrogra- Data Committee and spatial data within the Advisory phy and Elevation Terrestrial. Hydrography is com- Committee on Water Information. This Subcommittee prised of map layers depicting water features of the has established use cases for open water data in the landscape — streams, rivers, lakes, bays and the areas of flooding, water supply, and water quality, coastline, connected into a flow network. Elevation and seeks by a series of experiments to find the open Terrestrial describes vertical position above or below water data services which best inform decisions in a datum surface. The interaction of these two themes these areas. captures the age-old duality — water flows downhill The NWS collaborated with the academic commu- directed by the slope of the landscape, while the ero- nity coordinated through the Consortium of Universi- sive power of flowing water has itself been a major ties for the Advancement of Hydrologic Science, Inc. force in shaping the landscape over millennia. Sup- (CUAHSI) to conduct a National Flood Interoperabil- plemental Framework Themes relevant to water ity Experiment from September 2014 to August 2015 include Watersheds and Wetlands, which along with focused on developing a near real-time, high spatial Hydrography are part of the Inland Waters theme, resolution flood data, modeling, forecasting and inun- and Flood Hazards, Soils, Earth Cover, Geologic and dation mapping system. This experiment informed Climate, themes whose properties influence and are the flooding use case of the Open Water Data Initia- influenced by the movement of water through the tive. The results of the experiment will be reported in landscape. a later Featured Collection of articles in this Journal. During the first 10 years of the NSDI (1994-2004), The Federal Geographic Data Committee coordi- the focus was on the development of the framework nates the National Spatial Data Infrastructure themes, in particular the National Elevation Dataset, (NSDI), initiated in 1994 during the period of transi- National Hydrography Dataset, and later the Water- tion from paper maps to digital datasets in the U.S. shed Boundary Dataset. During the subsequent 10 Subsequently, “the NSDI has come to be seen as the years (2004-2014), the focus was on the integration of technology, policies, criteria, standards and people these datasets — the National Hydrography Dataset necessary to promote geospatial data sharing Plus (NHDPlus) dataset was formed as a synthesis of throughout all levels of government, the private and the elevation, hydrography, watershed boundary, and non-profit sectors, and academia” (http://www.fgdc. land cover datasets. gov/nsdi/nsdi.html, accessed August 6, 2015). A major The NHDPlus dataset partitions the nation’s drai- transition is occurring currently in GIS from provi- nage system into 2.67 million reach catchments, each sion of datasets to provision of data services, which is reach catchment draining to a single stream reach or acknowledged in the strategic plan for 2014-2016 for water feature, which are connected by the movement the NSDI whose first goal is to “develop capabilities of water through the sequence of reaches from any for national shared services” (Federal Geographic point in the landscape to the coast. Each reach catch- Data Committee, 2013). ment and the flowline within it carries a unique iden- In recent years, the capability for developing data tifier, or COMID, and by this means the land and services for water information has also been devel- water systems of the nation are connected. What oped, so it is useful to examine how data services for emerges is a single flow network across the continen- geospatial and water information could be inter- tal U.S., from atmosphere to oceans and from coast to linked. The purpose of this article is to explore what coast. The National Water Model computes the flow JAWRA 2 JOURNAL OF THE AMERICAN WATER RESOURCES ASSOCIATION OPEN WATER DATA IN SPACE AND TIME in all these reaches as a connected whole, each reach Information System for water quantity and quality, being fed by the drainage from the catchment that and the U.S. Environmental Protection Agency surrounds it. (USEPA) Storet (Storage and Retrieval) database for Attributes of the catchments describe properties of water quality. Beyond this information about moni- the local area while attributes of the flowlines toring the properties of the nation’s water, there are describe properties of the total upstream drainage important data on water operations, such as the vol- area. As the National Water Model is further devel- umes of storage and release from reservoir systems, oped, it is expected that the present continental scale and on water use in cities, agriculture, and industry surface water model will be complemented by a con- that form an important part of the nation’s water nected continental scale groundwater model. information base. Water information is collected by The strategic plan for 2014-2016 for the NSDI is all levels of government and there are hundreds if defined by Federal Geographic Data Committee not thousands of web sites that contain water data of (2013).