Stormwater runoff and water quality in urbanized watersheds of the greater Phoenix metropolitan area
Author(s):
- Nancy Grimm
- Stevan Earl
- Rebecca Hale
- Laura Turnbull
Abstract:
Urbanization dramatically alters watershed ecosystem processes. Land-use change and anthropogenic activities contribute to increased inputs of nutrients and other materials, while changes to land cover alter hydrology and the corresponding movement of materials. These changes have ramifications for both watershed processes and downstream systems. The impacts of urbanization on aquatic systems are well-studied, and frequently encapsulated in the ‘urban stream syndrome’ (Walsh et al. 2005) that describes, among others, increased nutrient loading and stream flashiness. However, there is some evidence that aridland cities behave differently (Grimm et al. 2004, 2005), and the complex dynamics among catchment characteristics, storm attributes, and runoff in highly urbanized settings of the Southwest remains poorly understood.
To enhance our understanding of stormwater dynamics and watershed functioning in aridland, urban environments, the Central Arizona–Phoenix Long-Term Ecological Research (CAP LTER) program began monitoring stormwater runoff at the outflow of the Indian Bend Wash (IBW) in 2008. The IBW is a major drainage in the greater Phoenix metropolitan area, draining much of the City of Scottsdale, and a tributary to the Salt River. A model of soft engineering, the IBW as it runs through the City of Scottsdale is comprised largely of a series of artificial lakes, parks, paths, golf courses, ball fields and other non-structural elements designed with the dual roles of providing outdoor amenities to the City residents and as a floodplain. A unique biogeochemistry of this novel system is detailed by Roach et al. (2008), and Roach and Grimm (2011).
Stormwater sampling is conducted near the outflow of the IBW ~0.6 km above its confluence with the Salt River. The sampling location coincides with a permanent USGS gauging station (USGS 09512162 INDIAN BEND WASH AT CURRY ROAD, TEMPE, AZ) that provides corresponding discharge data. Automated stormwater sampling equipment (ISCO® 6700 automated pump sampler) is used to collect discrete stormwater samples throughout the hydrograph of most runoff-generating storms.
Data and expertise garnered by the stormwater monitoring near the outflow of the IBW helped pave the way for a more expansive stormwater research effort facilitated by a leveraged grant from the National Science Foundation (DEB-0918457, NSF Ecosystems, 2009-13). Through the Stormwater Nitrogen in Arizona (SNAZ) project, ten hierarchically nested urban stormwater catchments in Scottsdale and Tempe, AZ were instrumented with automated stormwater samplers (ISCO® 6700 automated pump samplers). A subset of those 11 locations were fitted with bubbler modules (ISCO® 720 bubbler modules) for quantifying water height (and subsequently discharge), and tipping-bucket rain gauges (ISCO® 674). The ten study catchments differed in type of stormwater infrastructure, spanning a continuum from highly engineered stormwater infrastructure in older residential areas to non-engineered washes in the desert, but not in land-use type (land use in all study catchments is predominantly residential). As per sampling near the outflow of the IBW, discrete stormwater samples were collected from most runoff-generating storms at the outflow of the 10 study catchments from the fall of 2010 through the summer 2012. Rainfall samples were collected at a subset of the locations during several storms to provide data that would contribute to an assessment of sources of materials in runoff. Results of this study are detailed by Hale et al. (2014a, 2014b). Sampling at most locations ceased at the end of the SNAZ award period, but the CAP LTER continues its long-term monitoring of runoff near the outflow of the IBW.
Grimm N.B., Arrowsmith J.R., Eisinger C., Heffernan J., MacLeod A., Lewis D.B., et al. (2004) Effects of urbanization on nutrient biogeochemistry of aridland streams. In: Geophysical Monograph Series. (Eds R.S. DeFries, G.P. Asner and R.A. Houghton), pp. 129–146. American Geophysical Union, Washington, D. C.
Grimm N.B., Sheibley R.W., Crenshaw C.L., Dahm C.N., Roach W.J. and Zeglin L.H. (2005) N retention and transformation in urban streams. Journal of the North American Benthological Society 24, 626–642.
Hale R.L., Turnbull L., Earl S., Grimm N., Riha K., Michalski G., et al. (2014a) Sources and Transport of Nitrogen in Arid Urban Watersheds. Environmental Science & Technology 48, 6211–6219.
Hale R.L., Turnbull L., Earl S.R., Childers D.L. and Grimm N.B. (2014b) Stormwater Infrastructure Controls Runoff and Dissolved Material Export from Arid Urban Watersheds. Ecosystems 18, 62–75.
Roach W.J. and Grimm N.B. (2011) Denitrification mitigates N flux through the stream–floodplain complex of a desert city. Ecological Applications 21, 2618–2636.
Roach W.J., Heffernan J.B., Grimm N.B., Arrowsmith J.R., Eisinger C. and Rychener T. (2008) Unintended consequences of urbanization for aquatic ecosystems: a case study from the arizona desert. BioScience 58, 715–727.
Walsh C.J., Roy A.H., Feminella J.W., Cottingham P.D., Groffman P.M. and Morgan II R.P. (2005) The urban stream syndrome: current knowledge and the search for a cure. Journal of the North American Benthological Society 24, 706–723.
Keywords:
Temporal Coverage:
2008-01-29 to 2015-09-01Geographic Coverage:
Geographic Description: CAP LTER study areaBounding Coordinates:
Longitude:-112.044 to -111.856
Latitude:33.6618 to 33.4382
Contact:
Data Manager, Julie Ann Wrigley Global Institute of Sustainability, Arizona State University,PO Box 875402,Tempe
Methods used in producing this dataset: Show
Data Files (8) :
Tabular: runoffChemistry
Description: stormwater runoff chemistry during runoff-generating storms at CAP LTER
stormwater sampling sites
Column | Description | Type | Units |
---|---|---|---|
runoffLocation | location short code (reference location details in samplingLocation
table) |
Enumeration:
|
|
runoffDatetime | collection date and time |
||
replicate | sample replicate number |
number | |
analysis | analyte quantified (reference analysis details in the analyses
table |
Enumeration:
|
|
concentration | concentration of analyte |
milligramsPerLiter | |
dataQualifier | data qualifier flag |
||
comments | comments regarding sample |
||
blank | boolean value (TRUE or FALSE) indicating whether the sample is a
blank |
Enumeration:
|
Tabular: rainfallChemistry
Description: water chemistry of collected rainfall at CAP LTER stormwater sampling
sites
Column | Description | Type | Units |
---|---|---|---|
rainLocation | location short code (reference location details in samplingLocation
table) |
Enumeration:
|
|
rainDatetime | collection date and time |
||
replicate | sample replicate number |
number | |
analysis | analyte quantified (reference analysis details in the analyses
table |
Enumeration:
|
|
concentration | concentration of analyte |
milligramsPerLiter | |
dataQualifier | data qualifier flag |
||
comments | comments regarding sample |
Tabular: rainfall
Description: depth of precipitation as measured by tipping bucket rain gauge at CAP LTER
stormwater sampling sites
Column | Description | Type | Units |
---|---|---|---|
rainLocation | location short code (reference location details in samplingLocation
table) |
Enumeration:
|
|
rainDatetime | measurement date and time |
||
rainQuantity | precipitation amount |
millimeter |
Tabular: discharge
Description: discharge at CAP LTER stormwater sampling sites
Column | Description | Type | Units |
---|---|---|---|
dischargeLocation | location short code (reference location details in samplingLocation
table) |
Enumeration:
|
|
dischargeDatetime | measurement date and time |
||
waterHeight | water height above sensor |
meter | |
rawDischarge | discharge (Q) estimated from Manning equation |
litersPerSecond | |
editedDischarge | corrections to rawDischarge |
litersPerSecond |
Tabular: particulates
Description: mass of particulates in stormwater during runoff-generating storms at CAP
LTER stormwater sampling sites
Column | Description | Type | Units |
---|---|---|---|
particleLocation | location short code (reference location details in samplingLocation
table) |
Enumeration:
|
|
particleDatetime | measurement date and time |
||
replicate | sample replicate number |
number | |
filterWt | weight of clean, ashed filter |
gram | |
filterDryWt | dry filter weight |
gram | |
volFiltered | volume of sample filtered |
milliliter | |
filterAshWt | ashed weight of filter |
gram | |
dataQualifier | data qualifier flag |
||
comments | comments regarding sample |
Tabular: samplingLocation
Description: catalog of CAP LTER stormwater sampling locations
Column | Description | Type | Units |
---|---|---|---|
shortCode | location short code |
||
name | name of sampling location |
||
latitude | latitude of sampling location |
meter | |
longitude | longitude of sampling location |
meter |
Tabular: analyses
Description: catalog of water chemistry analytes measured as part of CAP LTER stormwater
monitoring
Column | Description | Type | Units |
---|---|---|---|
analysis | analyte quantified |
||
description | analyte description |
||
units | unit of measure |
||
instrument | analytical instrument |
Spatial Vector: stormwaterSamplingWatersheds
Description:
This zipped file contains a shapefile detailing the location and configuration of watersheds that are or have been sampled as part of the CAP LTER's research on stormwater monitoring in the greater Phoenix metropolitan area.
Horizontal Coordinate System:GCS_WGS_1984
Geometry Type: Polygon
Column | Description | Type | Units |
---|---|---|---|
ID | aribtrary identifier |
number | |
Site | watershed name |
||
Area | polygon area |
meter | |
Area_ha | polygon area |
hectare |