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Water lecture


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Water lecture

  1. 1. Water: Our Life Force <ul><li>75% of most living organisms are made up of water </li></ul>
  2. 2. Water <ul><li>What does water do? </li></ul><ul><li>Shapes the Earth </li></ul><ul><li>Nourishes and supports life </li></ul><ul><li>Moderates climate (with its high specific temperature) </li></ul><ul><li>Dissolves minerals </li></ul><ul><li>Irrigates crops and wild food plants </li></ul><ul><li>Provides hydro-energy sources </li></ul><ul><li>Is used in homes, for recreation, and travel </li></ul><ul><li>Creates wildlife habitat </li></ul>
  3. 3. Water <ul><li>The global distribution of water: </li></ul><ul><li>70% of the planet is water </li></ul><ul><li>Of this total water, 97% is saline or salty </li></ul><ul><li>Of this total water, 75% is locked up in ice and 13.5% is deep under the ground in aquifers </li></ul><ul><li>This leaves us with only 1/8% of fresh available water! </li></ul><ul><li>How can we develop a stewardship approach to managing water: our precious life source? </li></ul>
  4. 5. Think about how pitched roofs shed water…
  5. 6. Watershed Patterns in the Desert Southwest
  6. 7. <ul><li>Branching patterns abound in and around us </li></ul><ul><li>We are intimately linked with nature… </li></ul><ul><li>“ We are nature working” </li></ul><ul><li> -Penny Livingston Stark </li></ul>
  7. 8. Some Startling Numbers <ul><li>31 countries are now facing water scarcity & 1 billion people lack access to clean drinking water - United Nations </li></ul><ul><li>The World Bank estimates that by 2025, 2/3 of the world's population will suffer from lack of clean and safe drinking water </li></ul><ul><li>Five million deaths a year are caused by polluted drinking water </li></ul><ul><li>37% of rivers and streams in the US are unfishable/ un-swimmable and 50% of lakes and ponds </li></ul>
  8. 9. Combined Sewer Overflows
  9. 10. Drought <ul><li>Much irrigation (especially overhead) used on farms evaporates, and does not infiltrate the soil </li></ul><ul><li>Heavy machinery used in row-cropping also compacts soil and prevents infiltration </li></ul><ul><li>In the desert southwest, where lands have been de-forested, there is not enough moisture in the air to decompose felled trees; plants cannot re-grow and soil remains dry </li></ul>
  10. 11. Drought Evapotranspiration
  11. 12. Water and Efficiency <ul><li>Water weighs 8 lbs/gallon </li></ul><ul><li>Electricity is needed to pump water up from deep in wells (expensive in terms of time and money) </li></ul><ul><li>Alternately, water can be stored in a place where it can be moved and used freely, without the need for expensive to maintain and operate equipment </li></ul><ul><li>By using gravity, and catching water up high whether by pond, swale, cistern, or rain barrel, water can be used as needed </li></ul><ul><li>Tapping artesian wells and springs eliminates the need to drill or pump </li></ul><ul><li>Waterways offer channels of transportation </li></ul>
  12. 13. Guidelines for Water Harvesting <ul><li>Start at the top of a watershed and work down (it’s easier to make small adjustments up top rather than energy-intensive levees downstream…try to avoid “end of the tail-pipe” solutions) </li></ul><ul><li>Start small and simple with long, thoughtful observation </li></ul><ul><li>Plan an overflow route and manage the water as a resource </li></ul><ul><li>Spread and infiltrate the flow of water </li></ul><ul><li>Maximize living, organic ground cover (like clover, vetch, rye) </li></ul><ul><li>Continually reassess your system </li></ul>
  13. 14. Techniques: Catching, Storing, & Using Water Swales Rain Gardens Roof Catchment Infiltration & Soil Storage Keyline Design: Earthworks & Ponds Greywater Systems
  14. 15. <ul><li>NOTE: </li></ul><ul><li>Convex shapes in the landform sheds water (crowns on roads) </li></ul><ul><li>Concave shapes capture water (reservoirs) </li></ul>Concave Convex
  15. 16. Contours Digging swales (or narrow trenches) on contour catches uphill water and allows it to sink in to the ground are points of equal elevation on the landscape; contour lines connect these points
  16. 17. Swales on Contour <ul><li>Recharge groundwater </li></ul><ul><li>Slow down drainage and prevents erosion </li></ul><ul><li>Passively irrigates crops </li></ul><ul><li>Filters water before it enters the aquifer </li></ul>Vegetated Swale at Truckee Meadows, NV: Capturing and using water in the desert
  17. 18. Swale cross-section Water flowing from uphill, collecting in the swale
  18. 19. Rain Gardens
  19. 20. Rain Gardens
  20. 21. Roof Catchment <ul><li>Roofs are a wonderful resource with expansive surface area for catching rain water </li></ul><ul><li>1 square foot of surface with 1” of rainfall=5/8 of a gallon of water </li></ul><ul><li>Downspout disconnection allows water to be captured </li></ul><ul><li>A ceramic or sand filter is necessary for drinking rain water </li></ul><ul><li>Often, rainwater is used for irrigation </li></ul><ul><li>A “first flush” is necessary for first 3 minutes of a storm event—to avoid chemicals and debris </li></ul><ul><li>Incorporate an overflow mechanism </li></ul>
  21. 22. Multi-Barrel System
  22. 23. Above and below ground cisterns capture and store greater volumes of water
  23. 26. Storing Water in Soil <ul><li>Soil is made of organic material, minerals, air, water, and micro-organisms </li></ul><ul><li>Creating more humus (spongy decaying debris) builds soil and increases overall water security </li></ul><ul><li>Water can infiltrate humus and soil that is aerated and loose </li></ul><ul><li>Mulch stores water more efficiently than exposed soil </li></ul><ul><li>Porous space in soil can be created by: </li></ul><ul><ul><li>earthworms </li></ul></ul><ul><ul><li>animals like moles and gophers </li></ul></ul><ul><ul><li>decaying roots </li></ul></ul><ul><ul><li>compost </li></ul></ul><ul><ul><li>broad forks (see image) </li></ul></ul><ul><ul><li>plows and rototillers (although these can compact soil and harm delicate soil web) </li></ul></ul>