====== SA Cistern Notes ======
  * Rainfall data from TCEQ: http://www.tceq.state.tx.us/cgi-bin/compliance/monops/monthly_summary accessed 2007-05-07
  * (100x30)m2 0.3 ha total: (60x30)m2 0.2 ha orchard, (30x30)m2 0.1 ha garden vegetables (cultivated area)
  * NCSU has a nice report on [[http://www.ces.ncsu.edu/depts/hort/hil/hil-33-e.html|vegetable crop water needs]].
    * "application rates should not exceed[...]0.20 inch per hour for clay soils"
    * Vegetable crops require 2.5 cm/21days 2.5cm/5days
    * = 0.05-0.2 in/day = 0.125 to 0.5 cm/day ; 1.5 to 5 m3/day = 500 to 2000 m3/yr for 0.1 ha of crop area with year-round cultivation. ((0.1 ha * 10000 m2/ha * (0.00125|0.005) m/day *365.25 day/yr = (450|1800) m3/yr ))

A more realistic estimate of land use is needed; not all the area is under cultivation at all times.  Some area is used for walkways, and at any given time, some is fallow or planted with drought-tolerant (sometimes non-food) crops.   Also, some of this is orchard.
  * (60x30)m2 orchard planted (2x4)m is (15*15)=225 trees; 225*(0.025|0.040)m3/day = 5.6 to 9 m3/day during the growing season; less during winter.
  * (60x30)m2 orchard planted (4*5)m is (15*6)=90 trees; 90*0.11356((30gal/day)) = 10 m3/day 
  * 2000 m2 * 0.75 shaded * 10.764 ft2/m2 * 0.125 gal/day-shadedft2* 0.0037854 m3/gal = 7.6 m3/day

Here is some info for [[http://msucares.com/pubs/infosheets/is1449.htm|fruit tree irrigation]].
  * Plants over 4 feet in diameter: gal/day = 0.125 X shaded area
  * Plants less than 4 feet in diameter: gal/day = 0.17 X shaded area

It looks like a total of about 10 m3/day is needed, on average, for the 0.3 ha area of orchard and garden.  To go a full season (worst case for the garden) would take about 1000 m3 storage, a tank 25x10*4 m.

Approximate water requirements for mature trees and plants: 
^Crop^Gallons/day|
^Pecan| 70 - 105|
^Peach| 20 - 45|
^Apple| 20 - 45|
^Pear| 20 - 45|
^Sour cherry| 20 - 45|
^Apricot| 20 - 45|
^Plum| 6 - 12|
^Fig| 6 - 12|
^Persimmon| 6 - 12|
^Muscadine| 4 - 6|
^Blueberry| 4 - 6|
^Grapes| 4 - 6|
^Blackberry| 1 - 3|

Examples of daily water use. 
^Diameter or spacing (in feet)^Daily use (gallons)|
^40| 123 - 185|
^35| 94 - 140|
^30| 69 - 104|
^25| 48 - 72|
^20| 23 - 46|
^15| 13 - 26|
^10| 6 - 12|
^8| 5 - 7.5|
^6| 2.5 - 4.2|
^2 X 4| 0.7 - 1.2|
^4 X 4| 1.5 - 2.4|
^4 X 6| 2.2 - 3.5|
^4 X 8| 3 - 4.7|
^4 X 10| 4.1 - 6.0|
^6 X 10| 5.5 - 8.8|
^6 X 12| 6.6 - 10.6|