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Hydrologic Research and Findings

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We have found that the segments of stream that flow year-round have shortened in length substantially since the 1980s. Prior to 1984, the creek flowed continuously through the length of the Preserve year-round but, in contrast, since 1999 an average of only 28 percent of the stream channel within the Preserve has perennial flow. PAG’s hydrologic monitoring at Cienega Creek reveals that drought impacts have been noticeable since 2002. Although the creek saw some recovery in 2006-2008, the drought has since become more severe. In September 2009, the shortest flow extent for any autumn quarter was recorded, and in June 2011, the shortest flow extent ever was recorded.

The heavy monsoon of 2008 played a significant role in drought relief, improving groundwater levels so that seasonal fluctuation was nearly back to pre-drought levels. Then, with 50 percent of the average precipitation during the 2009 monsoon at Cienega Creek, the Preserve groundwater levels were reduced to the lowest levels of the heaviest part of the drought. The conditions have remained severe through 2010. The severity of drought impacts improved each month with winter rainfall through March 2010, decreasing from five feet below last year’s monthly groundwater depth to approximately three feet below. However, current groundwater levels remain significantly below pre-drought levels.

PAG contributes hydrologic monitoring data to the Local Drought Impact Group through the AZ Drought Watch, in order to help the Governor’s Drought Task Force assess the status of drought statewide. Thanks to Pima County support, PAG’s data is highly valued by this effort because it is the only consistent long-term data set that has been collected along Cienega Creek. Because Cienega Creek has been monitored for many years and is relatively un-impacted by urban development, these findings provide insight into how drought affects our natural environment.

� Cienega Flow Extent History May 1999-2011 � Variability of Flow Extent Handout (2011 Driest Year) � Local Drought Resources � Arizona Drought Status � Contribute Public Drought Observations

Cienega Creek Hydrologic Research and FindingsThe Pima County Regional Flood Control District has provided support over the years for PAG's monitoring program, in recognition that this unique perennial stream, with its pristine native riparian habitat, is a critical resource in southern Arizona.

Portions of both Cienega Creek and its tributary, Davidson Canyon, are protected through their designation as Outstanding Arizona Waters by the State. PAG Watershed Planning research reports contributed to this designation including reports on water quality, geology and source flows.

PAG's 20 years of hydrologic monitoring along Cienega Creek indicates that the region is in the midst of a long-term drought. A developing headcut, and erosion feature PAG began studying in 2002, surprised many who recognized the major successes of restoration, since the Pima County Natural Preserve was established in Lower Cienega Creek in 1986.

Annual Report The fiscal year 2009-2010 technical report for the Cienega Creek Natural Preserve Monitoring Project is shown below. This report summarizes PAG's groundwater and surface water monitoring between July 2009 and June 2010. The report contains monitoring methodology, comprehensive maps, and graphs of trends for surface flow volume, wet-dry flow lengths, groundwater levels and water chemistry. It also contains information on drought, erosion and repeat photography. This monitoring year was remarkable for having the lowest September water levels on record.

� Cienega Creek Natural Preserve Surface Water and Groundwater Monitoring Annual Report for the 2009-2010 Fiscal Year

ADWR Water Protection Fund Award for Headcut Study Interest in preserving Cienega Creek continues to drive monitoring, discussion and community engagement. In recent years, a large erosion feature (a headcut) developed, radically changing the stream habitat as it migrates upstream. Since 2002, the headcut has migrated over 1,200 feet and has grown to 12 feet deep and 20 feet wide. PAG has collected baseline data on structural habitat, vegetative cover and hydrologic conditions to evaluate the changes over a two-year period. The resulting report discusses the findings on the changes of the water table slope, the increase in fish habitat diversity, loss of vegetation cover and change in vegetation composition. Many new discussions have resulted from recent field trips, presentations and meetings regarding needs for restoration, potential causes, and possible impacts on other aspects of habitat. PAG is participating in a Sky Island/Sonoran Desert Restoration Network which formed to share information and to engage scientists, land managers, citizen volunteers and landowners throughout the region.

� Evaluation of Riparian Habitat and Headcutting Along Lower Cienega Creek

Drought Findings

KVOA - NASA images capture Tucson - then and now - July 26, 2012

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Record Low Creek Levels: NASA aerial imagery how lush the Santa Cruz River was when it flowed before major city growth. Rare remaining riparian areas in the county continue to be vulnerable to reduced water levels. KVOA interviews PAG's senior watershed planner to find out how current drought is impacting Cienega Creek. July 26, 2012, to see the full story visit http://www.kvoa.com/news/nasa-images-capture-tucson-then-and-now/

The extent of streamflow in Upper Davidson Canyon has declined substantially since 2003. Since the channel and pools completely dried out during the summer of 2005, PAG has not seen native fish there. Lowland leopard frogs are still present along the reach. This reach of the creek is currently under stress from off-road vehicle and cattle use, but the county has made efforts to exclude these activities from the riparian area.

� ADEQ Davidson Outstanding Water Designation � 2007 PAG Regional Council Resolution of Support for Davidson Canyon as an OAW

Highlights of PAG Studies on Cienega Creek

� 1990 Cienega Creek Unique Waters Nomination Report for Cienega Creek � 1998 Cienega Creek Surface Water and Groundwater Monitoring � 2000 Lower Cienega Basin Source Water Study � 2000 Cienega Creek Storm Flow Analysis � 2002 Changes in Channel Morphology Along Lower Cienega Creek 1980-1998 � 2003 Cienega Creek Non-Native Plant Species Study � 2003 Contribution of Davidson Canyon to Base Flows in Cienega Creek � 2003 Geologic Influences on the Hydrology of Lower Cienega Creek � 2004 Riparian Areas: Restoration and Management in Eastern Pima County � 2005 Davidson Canyon Unique Water Nomination Report

The PAG Watershed Planning library has additional publications on Cienega Creek from outside sources.

Take a virtual field trip to the headcut.

< 7/10 >

Davidson Canyon

©Pima Association of Governments | 177 N Church Ave, Suite 405, Tucson, AZ 85701 | Telephone (520) 792-1093, FAX (520) 620-6981

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Cienega Creek

Three Bridges

Marsh Station Rd.

I-10

Most Recent - June 2011

Percent Flowing (Wet) from June 1984 - 2011

Variability of Flow Extent Along Lower Cienega Creek

PAG monitors streamflow in the Pima County Natural Preserve. June is the driest month in Arizona, making it the best time to estimate the minimum perrenial streamflow. Prolonged drought impactsthe creek by decreasingflow amounts and extents.June 2011 exhibited thelowest June flow extenton record.

Created: Nov. 2011

Cienega Creek

David

son C

anyo

n

Three Bridges

Marsh Station Rd.

I-10

Wettest Drought Year - June 2001

Cienega Creek

Three Bridges

Marsh Station Rd.

I-10

Previous Driest Year - June 2005

David

son C

anyo

n

Miles0 1 20.5±±

Montgomery &AssociatesMonitoring

PAGDrought

Monitoring

No Available Data

Flowing Stream ReachDry Stream BedLower Cienega Creek Preserve

13%wet

87%dry

16%wet

84%dry

49%wet51%

dry

1984

1985

1986

1987

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

2005

2006

2007

2008

2009

2010

2011

0%10%20%30%40%50%60%70%80%90%

100%

Marsh Station

Rd

Marsh Station Rd

Ci e

n e g a C r e e k N a t u r a l P r e s e r v e

Cienega Creek

1 9 9 9 t o 2 0 1 1June Annual Wet/Dry Status

1999200020012002200320042005200620072008200920102011

0 0.25 0.5

Mi les

1 Mile

Bars represent wet reaches in a linear fashion for each June, 1999–2011. The bars are spatially distributed to correspond to 8 miles of mapped creek length. The colors alternate by year for visual aid. Using GPS technology, teams walk the creek to map where it intermittently flows.