KJacobs

Impacts of Growth: the Water Example: 

Impacts of Growth: the Water Example Learning to Grow: Options for a Changing Landscape Tombstone, Arizona April 7, 2007 Katharine Jacobs

Arizona Water Institute: 

A consortium of Arizona’s universities focused on improving quality of life in Arizona and throughout the world through water research, education and technology… 400 water related faculty/staff 3 state agencies Public and private partners 18 projects under way Arizona Water Institute

Defining the problem: Role of Groundwater in Arizona Water Use : 

Defining the problem: Role of Groundwater in Arizona Water Use 68% 7% 25% Groundwater mining causes subsidence and affects surface water flows Over 40% of Arizona water use and 60% of potable supplies are from Groundwater. Arizonans use over 7 million acre feet of water per year; almost half from the Colorado (2.8 MAF).

Water Management in Arizona: 

Water Management in Arizona 1980 Groundwater Management Act; AMAs and INAs Groundwater and surface water systems are managed separately Water supply and water quality, with some exceptions, are managed separately Safe yield vs sustainability

Water Management Background: AMA vs non AMA : 

Water Management Background: AMA vs non AMA Rural Arizona 87% of land area 47% of total water use 18% of the state’s population

Slide6: 

Arizona Dept. of Water Resources

Water Management in AMAs:: 

Water Management in AMAs: Management goals Groundwater rights and permits Well metering, annual reports and fees Well impact assessment Mandatory conservation for large users Assured water supply for subdivisions No new agriculture Monitoring and conservation assistance

Water Management Outside of AMAs: 

Water Management Outside of AMAs No limits on groundwater withdrawals No well measurement or reporting No well impact assessment No mandatory conservation Adequacy instead of Assured Water Supply: no consumer protection (current proposed amendments) No limit on new agriculture (except in INAs)

The San Pedro: Balancing Human and Environmental Needs: 

The San Pedro: Balancing Human and Environmental Needs

ADWR USP Water Budget (2002): 

ADWR USP Water Budget (2002) INFLOW: Natural recharge 15,000 Acre-feet (AF) Underflow from Mexico 3,000 AF OUTFLOW: Baseflow 3,250 AF Groundwater withdrawals 16,500 AF Evapotranspiration 7,700 AF Underflow downstream 440 AF TOTAL -9,900

2002 Sector Water Demand - ADWR: 

2002 Sector Water Demand - ADWR Agricultural Demand 31% of total water demand (Pomerene/St. David) Groundwater (76%) Surface water (24%) Municipal Demand 61% of total water demand Water providers 60% Domestic (Exempt) Wells 30% Fort Huachuca 10% Groundwater (95%) SW (1%) Effluent (4%) Industrial/Stock Demand 8% (golf courses, sand & gravel, etc.); 100% GW

Exempt Well/Wildcat Subdivision Issues: 

Exempt Well/Wildcat Subdivision Issues Exempt wells: 35 gallons per minute or less, no regulation other than well drilling requirements Lot splitting vs. subdividing Wildcat subdivisions (health, safety, access, infrastructure issues)

Private Wells vs Municipal Systems: 

Private Wells vs Municipal Systems Private wells use more water; exempt wells are unmetered, no incentive to conserve other than power costs, no way to detect leaks Economies of scale – average costs of water if include capital costs and O&M Regulatory/water quality/monitoring benefits Well spacing Drought planning, conservation options

Emerging Water Issues: 

Drought and climate change implications for water management Increasing complexity and legal challenges to management system Limits on effectiveness of conservation efforts Willingness to pay for long term solutions and make difficult political decisions Emerging Water Issues Santa Fe Ranch, ADWR Santa Cruz River, Carmen – ADWR

Slide15: 

Intergovernmental Panel on Climate Change (IPCC) 3rd Assessment Arizona Climate Divisions Arizona Climate Division 2 Winter Precipitation Reconstruction Reconstructed precipitation over the last 1000 years suggests that: 1) the late 20th century Arizona was also anomalously wet (by 25%)… (new results from UA Prof. M. Hughes and team) Jonathan Overpeck, ISPE

Slide16: 

Intergovernmental Panel on Climate Change (IPCC) 3rd Assessment Arizona Climate Divisions Arizona Climate Division 2 Winter Precipitation Reconstruction …and 2) that droughts lasting a decade or more are not that uncommon Jonathan Overpeck, ISPE

Slide17: 

Conclusions: • even in the absence of significant climate change, Arizona should plan for less precipitation and the possibility of long droughts (10-20 years possible) • given continued climate change, Arizona will likely become drier and more prone to drought • warmer temperatures increase demand while decreasing supplies Jonathan Overpeck, ISPE

San Pedro Issues Summary: 

San Pedro Issues Summary Significant growth pressure Transient population Exempt wells and lot-splitting Limited access to alternative supplies Inadequate local/regional control of water supplies and land use River preservation issues

Lessons Learned in Arizona: 

Lessons Learned in Arizona Groundwater is seriously undervalued Balance between protection of property rights and public interest must be achieved Conservation, conversion to renewable supplies and reuse are key to sustainability There is no free lunch – supply side solutions have impacts Surface water and groundwater should be managed conjunctively Need long-term perspective on climate and water supply to plan for the future; need to plan for drought when it is not a crisis

Challenges and Opportunities: 

Challenges and Opportunities Increase local/regional control of water supplies; connect water management and land use More tools for county land use planners to control density and water-dependent uses (transferable development rights, ordinances, adequacy, etc) Water harvesting, grey water use, effluent reuse Dual plumbing, maximize recycling capacity Tax incentives for groundwater protection activities

Slide21: 

Control domestic wells and lot-splitting Reduce size of “subdivisions,” enforce existing rules Limitations on new exempt wells in vulnerable areas Encourage development of municipal water and sewer systems