Channeling the water data deluge: a system for flexible integration and analysis of hydrologic data

Figures & data

Figure 1. Workflow for exploratory analysis of hydrologic data.

Figure 2. Overview of HydroCloud system architecture.

Figure 3. Overview of components in a document database.

Figure 4. HydroCloud document database schema.

Table 1. Data dictionary for HydroCloud database.

Field Name	Data type	Description
Stream flow document
Site ID	String	USGS assigned site ID for stream flow gauges
Date/Time	ISO 8601 Timestamp (UTC)	Timestamp of stream flow measurement
Data	Embedded document	Embedded document to store stream flow measurement
Data.GaugeHeight	Double	Height of water surface measured in feet
Data.Discharge	Double	Stream flow measured in cubic feet per second
Precipitation grid document
Date/Time	ISO 8601 Timestamp (UTC)	Timestamp of precipitation grid
Precip grid	Array	4 km hourly NEXRAD precipitation accumulation grid for CONUS
Precipitation statistics document
Site ID	Text	USGS assigned site ID for stream flow gauge associated with document
Date/Time	ISO 8601 Timestamp (UTC)	Timestamp of precipitation grid
Basin average	Double	Hourly area averaged precipitation for catchment (mm/km^2)
Maximum	Double	Hourly maximum precipitation cell in basin (mm)
Minimum	Double	Hourly minimum precipitation cell in basin (mm)
Mean	Double	Hourly mean precipitation (mm)
Standard deviation	Double	Standard deviation of hourly precipitation in catchment (mm)
Percent coverage	Double	Percent of catchment covered by precipitation
Distance weighted	Double	Mean precipitation weighted by distance from stream gauge (mm)
Mask document
Site ID	String	USGS assigned site ID for stream flow gauge associated with document
Mask grid	Boolean array	Mask grid used to extract precipitation data for each catchment.
Spatial coordinate document
Latitude grid	Array	Array of latitude coordinates that correspond directly to precipitation grid
Longitude grid	Array	Array of longitude coordinates that correspond directly to precipitation grid
Site Info document
Site ID	String	USGS assigned site ID for stream flow gauges
Site name	String	Name of USGS stream flow gauge site
Site type	String	Type of site – in this application stream flow
Latitude	Double	Latitude coordinate of site
Longitude	Double	Longitude coordinate of site
State code	Double	State of site
Gage altitude	Double	Elevation of site
Drainage area	Double	Drainage area of site catchment
Contributing area	Double	Contributing drainage area to stream gauge
Catchment document
Type	Text	GeoJSON feature type
Geometry	Embedded document	Embedded document containing spatial feature
Geometry.Type	String	Spatial feature type
Geometry.Coordinates	List	Coordinates of the spatial feature
Properties	Embedded document	Embedded document containing attributes of spatial feature
Site ID	String	USGS assigned site ID for stream flow gauges
Area	Double	Area of polygon feature
Area units	String	Units of area field
Percent impervious	Double	Percent of catchment covered by impervious surface

Figure 5. ETL workflow for processing NWIS stream flow data.

Figure 6. ETL workflow for processing watershed boundary GIS files.

Figure 7. ETL workflow for processing Stage IV precipitation data.

Figure 8. Example precipitation and stream flow visualization created from sample database query.

Figure 9. Overview of HydroCloud web service architecture.

Figure 10. Example web service result showing Stage IV precipitation JSON return.

Figure 11. HydroCloud web interface showing NWIS stream gauge locations and NEXRAD radar data.

Figure 12. HydroCloud web interface showing a plot of stream (top) and precipitation data (bottom).

Figure 13. Response time for HydroCloud web services.

Table 2. Sites selected for analysis of hydrologic response using the HydroCloud web interface.

Site ID	Site name	Area (km^2)	Percent impervious surface
01589000	Patapsco River at Hollofield, MD	739	3.1
01582500	Gunpowder Falls at Glencoe, MD	414	0.9
01594000	Little Patuxent River at Savage, MD	254	8.5
01580000	Deer Creek at Rocks, MD	244	1.4
01594526	Western Branch at Upper Marlboro, MD	234	16.0
01649500	Northeast Branch at Anacostia River at Riverdale, MD	188	20.0
01589352	Gwynns Falls at Washington Blvd. at Baltimore, MD	159	27.3
01583500	Western Run at Western Run, MD	156	0.7
01586000	North Branch Patapsco River at Cedarhurst, MD	145	4.2
01582000	Little Falls at Blue Mount, MD	139	0.9
01651000	Northwest Branch Anacostia River, Hyattsville, MD	128	19.2
01584500	Little Gunpowder Falls at Laurel Brook, MD	94	1.1
01581700	Winters Run near Benson, MD	90	2.7
01586610	Morgan Run near Louisville, MD	73	1.0
01589440	Jones Falls at Sorrento, MD	65	5.1
01583600	Beaverdam Run at Cockeysville, MD	54	13.2
01586210	Beaver Run near Finksburg, MD	37	3.4

Figure 14. Hydrograph and precipitation statistics for the Patapsco River at Hollofield, MD for Hurricane Sandy (29 October 2012).

Figure 15. Hydrograph and precipitation statistics for the Patapsco River at Holofield, MD for May 2014.

Figure 16. Hydrograph and precipitation statistics for Morgan Run near Louisville, MD Hurricane Sandy (29 October 2012).

Figure 17. Hydrograph and precipitation statistics for Morgan Run near Louisville, MD for 16 May 2014.

Table 3. Statistical significance of relationships.

		p value		adj. R ^2
Independent	Dependent variable	May value	Sandy value	May value	Sandy value
Watershed area	Total stream discharge	<0.001	<0.001	0.95	0.74
	Total precipitation	<0.001	<0.001	0.96	0.92
	Base discharge	<0.001	<0.003	0.80	0.42
	Peak discharge	0.018	0.006	0.27	0.37
	(Index of Hydrologic Alteration)	0.336	0.778	−0.00	−0.06
	% Runoff	0.043	0.008	0.19	0.34
	(May lag time)	0.09		0.13
% Impervious	Index of Hydrologic Alteration	0.002	<0.001	0.46	0.56

Note: Insignificant relationships are in parentheses.

Figure 18. The effect of percent impervious area on the index of hydrologic alteration. Based on data for 29 October 2012 (Hurricane Sandy) and 17 watersheds in central Maryland Piedmont.

Figure 19. The effect of watershed area on percent runoff. Percent runoff is calculated as the ratio of total stream discharge to the total volume of precipitation during Hurricane Sandy.