Lecture 11: Water and Water Management

Introduction

  • Topic: Water and water management in horticulture, specifically in California.

  • Major focus areas:

    • Landscape water use in California.

    • Key laws regulating water use in landscaping.

    • Principles of landscape and garden water conservation.

    • Water efficiency, irrigation processes, and scheduling based on weather data.

  • Learning Outcomes: Fundamental understanding of soil-water relationships in garden landscapes.

Challenges and Opportunities in Water Management

  • Water Availability in California:

    • California faces significant water challenges, largely not due to scarcity but infrastructure issues.

    • Historical context of water use and management leads to high conflict and legal issues.

  • Water Inefficient Practices:

    • Traditional understanding mischaracterizes agriculture’s role in water consumption (15-20% vs. 80% often claimed).

    • Environment receives the largest share of water resources, approximately 80% of total water through rain and snow.

    • Urban and agricultural water consumption statistics:

    • Urban use contributes to about 4.5% of captured water in California.

    • Landscaping uses only about 9% of total water but offers significant savings opportunities.

  • Infrastructure and Capture Issues:

    • Underdeveloped water infrastructure leads to inefficient capture, retention, and distribution of water.

Water Cycle and Evapotranspiration

  • Water Cycle Explanation:

    • Evaporation from land and water surfaces, transpiration from plants, combined causes evapotranspiration.

    • Evapotranspiration is critical for evaluating how much water is needed for irrigation.

    • Measured in inches over various time periods.

Challenges of Freshwater Availability

  • Majority of Earth's Water: 39% is freshwater, of which 2.5% is accessible; bulk is in glaciers and underground.

  • Importance of Aquifer Recharge:

    • Aquifers are being depleted faster than they can be replenished (historical decline of approximately one foot per year).

    • Quality of water degrades as aquifer levels drop, necessitating deeper drilling for clean water.

Water Use in Urban Landscapes

  • Urban Water Use Patterns:

    • Focus on managing water efficiently due to restrictions and environmental concerns.

    • Importance of understanding local watershed:

    • Example: Sacramento and its drainage to the Sacramento River and Folsom Lake.

Rainwater Harvesting and Efficiency Practices

  • Rainwater Capture:

    • Encouragement of practices like rainwater harvesting using roofs to collect runoff. Example: 1 inch of rain can yield approximately 650 gallons from 1000 square feet of roof.

  • Importance of Soil Quality:

    • Soil depth and quality dictate plant health and water holding capacity.

    • Healthy soil yields better water retention and reduces irrigation needs.

Water Efficiency in Landscape Design

  • Legislation: Assembly Bill 1881 (2006) - Model Water Efficient Landscape Ordinance

    • Mandates water conservation standards for landscaping based on plant types and irrigation methods.

    • Guidelines for soil preparation, irrigation design, water budgeting, and establishment of appropriate water usage.

Irrigation Systems and Technology

  • Types of Irrigation Approaches:

    • Overview of different nozzles (spray heads vs. rotary nozzles) and their efficiencies.

    • Discussion of drip irrigation advantages: uses less water and more efficient in delivering water to plants.

    • Importance of auditing irrigation systems:

    • Verification of water use through audits to ensure efficiency and address leaks or malfunctions.

  • Calculation Techniques:

    • The meteorological basis for landscape irrigation involves knowing local evapotranspiration rates and plant watering needs.

    • Formulas for calculating water need and determining run times for irrigation systems are shared.

Opportunities in Water Management Careers

  • Emerging career prospects in landscape irrigation and water management:

    • Potential for rewarding careers in designing, installing, auditing, and maintaining irrigation systems.

  • Certificate Programs:

    • Certificate in Sustainable Irrigation Water Management Technology offered, linking coursework to practical skills and knowledge.

  • Recap of the need for efficient water management practices in landscaping.

  • Encourages students to integrate learned techniques into personal and professional landscapes for improved sustainability.

  • Encourages questions via various communication platforms (email, Canvas discussion boards, etc.).

Supplementary Notes

  • Importance of creating landscapes that remain healthy even during drought conditions, encouraging long-term water conservation strategies.