About CUAHSIThe Consortium of Universities for the Advancement of Hydrologic Science, Inc. (CUAHSI) is an organization representing 120+ universities in the US and 11 international affiliates. As part of its mission, CUAHSI supports the development of cyberinfrastructure for the hydrologic sciences. The CUAHSI HIS (Hydrologic Information System) project is a multi-year multi-institution effort focused on consistent management and integration of observational data available from several federal agencies (USGS, EPA, USDA, NOAA, etc.) as well as published by academic investigators.

Databases Analysis

Models

Rainfall & Snow

Water quantity and quality

Remote sensing

Meteorology

Soil water

The project’s focus is enhancement of hydrologic science by facilitating user access to more and better data for testing hypotheses and analyzing hydrologic processesThis involves:• assembling and querying integrated nations’s repository of water data• linking small integrated research sites with global climate models• integrating data from multiple disciplines to understands controls on hydrologic cycle• developing mechanisms for publishing heterogeneous government and academic data

Publishing hydrologic observationsService-oriented architecture for hydrologic dataCUAHSI HIS develops service-oriented architecture for hydrologic research and education, to enable publication, discovery, retrieval, analysis and integration of hydrologic data. The project team has defined a common information model for organizing hydrologic observation data, designed a common exchange protocol (Water Markup Language), created a collection of SOAP web services (WaterOneFlow services) that provide uniform access to different federal, state and local hydrologic data repositories, and developed mechanisms for ontology-based data registration and discovery.

CUAHSI member universities in the US

HIS Central

Register Service

Upload Icons, Test

Service

Service is Harvested

Tag Variables

with ontology concepts

Data is available

in Hydroseek

Observations Data Model WaterML

WaterML

WaterOneFlow Web Services Semantic Mediation

Test bed HISServers

Central HIS servers

ArcGIS

Matlab

IDL, R

MapWindow

Excel

Programming (Fortran, C, VB)

Desktop clients

Customizable web interface (DASH)

HTML - XML

WS

DL

- SO

AP

Modeling (OpenMI)

Global search (Hydroseek)

WaterOneFlow Web Services, WaterML

Con

trol

led

voca

bula

ries

Met

adat

aca

talo

gs

Ont

olog

y

ET

L s

ervi

ces

HIS LiteServers

External data providers

Other popular online clients

ODM DataLoader

Streaming Data Loading

Ontology tagging (Hydrotagger)

WSDL and ODM registration

Data publishing

ODMTools

Server config tools

HIS CentralRegistry & Harvester

This system is implemented as a collection of HIS Servers deployed at NSF-supported Hydrologic Observatory test beds across the nation. Several HIS Server are deployed at other partner universities and agencies, and internationally.

Deployment

Science goals

End-to-end three-tier solution: frompublication and registration to discovery and analysis of hydrologic observation data

Vocabularies used by each data source, are matched up with a common controlled vocabulary. In the process of water data service registration, variable names in each source are associated with concepts in a CUAHSI HIS ontology. This provides for semantics-aware data discovery and integration regardless of naming conventions or synonyms used by individual sources.

Observations Data Model (ODM) is a standardized and community- tested relational schema for storing hydrologic observation data and a sufficient amount of metadata, in a form that aids in effective sharing and analysis of information from disparate sources. ODM Data Loaders support efficient ingestion of data and metadata from files or data streams. ODMTools software is designed to manage and quality

Water Markup Language (WaterML) is a standard XML schema for hydrologic time series, designed to support exchange of hydrologic information between servers and clients within HIS. It contains general constructs describing sites, variables, time series, and data values. Designed to be the least barrier for adoption by hydrologists, WaterML

control of information in ODM. Loading investigator data into ODM, and providing access to the data via generic ODM web services, are the first steps towards sharing and integrating hydrologic observations within the Hydrologic Information System.

relies on both the ODM relational schema adopted for managing data from academic projects, and the data and metadata available from government hydrologic repositories at the national and state levels. WaterML 1.0 specification is available as an OGC Discussion Paper at http://www.opengeospatial.org/standards/dp.

WaterOneFlow Web Services provide a uniform way to query and access observations data and metadata within HIS, regardless of intricacies of individual data sources. The following core methods are supported: • GetSites • GetSiteInfo• GetVariableInfo• GetValues

WaterOneFlow method calls return WaterML-compliant documents to HIS clients. The list of data sources that are accessed via WaterOneFlow services include: USGS National Water Information system (Daily Values, Ground Water, Instantaneous Irregular Data, Unit Values), EPA STORET, USDA Snowpack Telemetry (SNOTEL), NCDC ASOS, MODIS,

DAYMET, NAM12K, as well as over 40 observation networks contributed by academic research projects and made accessible via ODM Generic Web Services. The WaterOneFlow services and WaterML are being adopted by HIS partners, including government agencies.

While syntactic heterogeneity is managed by water data being described using ODM and WaterML, and accessed via uniform Web services, semantic differences across observation networks require a different approach.

CUAHSI HIS supports data publication workflow for hydrologic observations. The steps include:• Loading data into ODM instance and configuring a Generic ODM web service providing access to the data (typical for relatively small academic projects) OR Configuring a custom WaterML-compliant web service and assembling a source metadata catalog (typical for large remote repositories)• Registering the new water data service at a local HIS Server (to be accessible via DASH, Data Access System for Hydrology), AND/OR Registering the service at the HIS Central, a web application for managing and exploring WaterML-compliant services.

By indexing both government and academic water data services, HISCentral provides a gateway to the largest collection of water observations in the nation.

Once a new water data service is registered, tested and described at HISCentral, an HISCentral’s harvester retrieves site and variable metadata, and the data series information.

Adding a water data service to the integrated metadata

catalog

The next step is tagging the harvested variables using CUAHSI ontology concepts, and making the new water data service appear in Hydroseek, a web application for ontology-based and map-based search and retrieval of hydrologic data from multiple networks.

Links HIS Central: http://hiscentral.cuahsi.org/

CUAHSI HIS: http://his.cuahsi.org

Hydroseek: http://www.hydroseek.net

HIS Wiki @ SDSC : http://river.sdsc.edu/wiki

Mailing list: subscribe at https://lists.sdsc.edu/mailman/listinfo/his

Hydrologic Information System for the Nation