Hydrologic Perspectives - southern Arizona and the San Pedro Watershed

James Callegary

March 26, 2019 Lower San Pedro Collaborative

U.S. Department of the Interior

U.S. Geological Survey

Concepts in Groundwater Hydrology:

Regional Aquifer Levels and Horizontal gradients

Transpiration

water.usgs.gov/edu

Concepts:

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• Gaining and Losing Streams

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• Baseflow

Barlow and Leake, 2012

Concept: Rainfall and Runoff

Transpiration

Runoff =

Base flow

Barlow and Leake, 2012

Concepts: Near-stream alluvial aquifer water levels

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Barlow and Leake, 2012

Upward Groundwater Flow

Concepts: Near-stream alluvial aquifer water levels

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Barlow and Leake, 2012

Downward Groundwater Flow

Concepts: Perched Water Table – Spring Flow

Transpiration

Concept: Springs

http://www.physicalgeography.net/fundamentals/8m.html

Concepts: Regional Aquifer Levels and Horizontal gradient: No Well

Barlow and Leake, 2012

Concepts: Regional Aquifer Levels and Horizontal gradients: New Pumping Well

Barlow and Leake, 2012

Barlow and Leake, 2012

Concepts: Regional Aquifer Levels and Horizontal gradients: Pumping Well - Capture

Barlow and Leake, 2012

Concepts: Regional Aquifer Levels and Horizontal gradients: Pumping Well – Stream Capture

Concept:

• Disconnected Stream

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• Ephemeral Stream

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• wet-dry status

Barlow and Leake, 2012

Ephemeral and Intermittent Streams

• Ephemeral and intermittent streams make up more than half the length of all rivers and streams globally
• Characteristics of both perennial streams and floodplains, but fill an ecohydrologic niche that is different from either
• Provide water for humans and corridors for the movement and cycling of water, energy, organisms, sediment, and organic matter
• Flow of shallow groundwater under ephemeral and intermittent stream channels can be critical for sustaining downstream perennial reaches, and supporting hyporheic organisms

Patagonia Mountains - Fractured Rock Hydrology

From: Mark Williams, CU Boulder

Forensic Hydrology

Hydrologic Modeling

• Preliminary estimates of water budget components
• Assess potential locations of groundwater-surface-water interactions, erosion and water quality risks
• Tool to aid and explore management decisions
• Movement of chemical constituents

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Wildfire

• One of the most abrupt and potent watershed alteration mechanisms in any ecosystem

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• Model results of future climate and wildfires - ignitions and area burned - predict dramatic increases in wildfire frequency and extent, and in post-fire erosion rates

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• Geomorphic trigger affecting physical and chemical transport including C and N both during and after fires

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• Majority of erosion occurs during the first five years

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• Charcoal, resistant to biological oxidation, can be transported into and stored in soil horizons

Colorado River Delta Restoration – Minute 323

• Ecological and Social Benefits

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• System Conceptual Model
• Well functioning vs impaired
• Restore to what?

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• Measuring Outcomes – Indicators

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• Adaptive Management

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• Sharing Information
• Data Management
• Communication

US-Mexico Transboundary Aquifer Assessment

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• Physical Geography
• Surface-Water Hydrology and Hydrometeorology
• Conceptual Geologic Model
• Hydrogeology
• Piezometry and Hydraulic Parameters
• Hydrogeochemistry
• Conceptual and Numerical Groundwater Models

Social science in applied hydrologic research

• Economic, cultural, historical, and socio-political setting
• Legal framework, institutional setting
• Identification of team members
• Resources: technical and financial
• Planning and decision-making
• Communication: internal, stakeholder, scientific community

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Watershed Degradation in the Southwest United States

• Result of natural and anthropogenic processes: pumping, agriculture, development, grazing, climate change, drought, infestation, deforestation, and changed management regimes such as removal/suppression of fire in grasslands and forests

Watershed Restoration with Erosion Control Structures

• Erosion control structures (ECS) used for thousands of years and currently in use around the world
• ECS can provide multiple benefits to degraded riparian and aquatic ecosystems
• increase channel roughness (Nilsson et al., 2005), and decrease peak flow (Norman et al., 2015)
• increase deposition of sediment and coarse particulate organic matter (Koljonen et al., 2012)
• Promote establishment of plants (Norman et al., 2014)
• Promote infiltration, recharge and storage of water; raise water tables
• Reduce erosion and stabilize hillslopes
• Increase capacity for water, carbon and nitrogen storage in captured sediments
• Increase hydroperiod

Restoration Effects on C and N Transport and Storage

• Watershed and riparian restoration often entail the installation of water and sediment detention ECS such as gabions or one-rock dams.
• What is the source of the organic matter that builds up in the detained sediments?
• Is it transported?
• Or does it result from in situ production by plants and microbial communities?
• Can we store it long term?

Hydrologic Concepts

Hydrology - Middle San Pedro�(Cordova et al, 2015)

Hydrogeologic Units

Hydrology - Middle San Pedro�(Cordova et al, 2015)

Hydrology - Middle San Pedro�(Cordova et al, 2015)

Water Level Contours

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