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A
access (tank) 9,53,55,56,57,109
form for 102
hatch 117
lockable 52
pressure-tight 56
sealing 52
Acrylonitrile Butiadene Styrene (ABS) 94
ac (acre) 90
additives 39
aerator.See inlet aerator
aesthetics 31
afy (acre-feet per year) 90
agricultural chemicals 23
air, displaced 8
airlock 9
air gap 55
air pressure level gauge 70-89
air vent.See vent, air
alarm 35,71
algae 9,22,27,65,76
aluminum 43
animal droppings 9
anti-seep collars 25
apartment 88-89
appropriate technology 3
aquaculture 21,23
aquatic plants 21,27
aquifers 16-20,76,88
artesian 18
confined 18
contamination 17
fissured 18
gravity 18
high 22
increasing water in 19-20
injection wells 19
overdrafting 19,83
perched 18,83
protecting quality 20
recharge 7,19,21
saltwater intrusion 18,19,20
subartesian 18
types 18
architectural guidelines 52
area, formulas for 90
Arizona desert 88
armature (for ferrocement) 95,107,114,117
atm (atmosphere) 90
attrition (of pathogens) 2,10,11
B
bacteria 5,9.See also pathogens
anaerobic 10
a health problem? 11
fecal 7
indicator 13
bacteria, beneficial 72
bacterial regrowth 11,12,76
baked enamel.See porcelain-bonded carbon steel
ball valve.See valves, ball
bathing 7
bathtubs 7
beavers 27
bedrock, fissured
and 23
bending force 91,92,93
bentonite clay 24,61,109
biological hazards.See pathogens
birds 22
bisphenol-A 94
boilers 11
bore.See wells
Branched Drain Greywater Systems 124
brass 41,42
brass fittings 56,114
break pressure tanks 54
brick (tank material) 44
bucket 56
Builder's Greywater Guide 124
building department 52
bulkhead fitting 45,87
buried storage 31,38,44,47,49,65,74
collapse of 32
burning brush 79
C
calcium, precipitation 11
capillary connection 16
cedar 45
cement 6
cement mixer 108
cheap and easy 8
check valve.See valves, check
chicken wire 117
chlorination 9,10,12,27,67,76
cigar shape 32
circumference of a circle 90
clarified septic effluent 10
clay (material for storage) 22,44
clear tube (as level indicator) 70-89
climate 20
cold joints (in concrete) 107
coliforms.See bacteria
coliscan plate 11
color coat 106
combined drain/outlet.See drain, combined with outlet
components
overview 28
spreadsheet 28
compound curves.See curves, compound
compression force 92,93
concrete 11,22,32,44
fly ash in 39
forms 96-107
conduction 54
confining layers 18
conical floor.See floor, conical
conjunctive use 19
conservation
in emergency 35
contact time 12
contamination.See toxins
context 3,14,95
convection 54
conversions 90
copper 42-43
pipe 54
corks 62
corrosion.See rust
cost 5,8,16,22,24,27,50-51
21
really cheap storage 50
cost-benefit 4
Costa Rica 88
CPVC 54
crayfish 27
Create an Oasis with Greywater 124
creeks 14,18
creek direct.See source direct
critter-proofing 8,50,63,64,65
crud 8
Cuba 54,58
curing 96
too fast 100
curves 71
compound 93,116,117
simple 93
cut 48
D
dams 20
dead storage 55
decorative 75
deflocculation 10
demand.See water
design
contexts 6
ecological 3
life 7
principles 3-8
trade-offs 4
disaster 1
sizing storage for 35
disinfection 11
byproducts 10,12
decay 12
dissolved oxygen.See oxygen
distribution system 10
diversions 23,25,83,85
dobies 108,113
size 115
drain 58-62
capped 59,60
center 111
combined with outlet 45,58,60
construction details 61,109
extension 71
for buried tanks 31
for pond 24,25
in wood tank 45
location 59-65
low tech 61
options 61
retrofit
plastic tank 60-65
steel tank 58,59
size 62
sump 60-65,104
drainage 48
dredging 27
drinking water 7,88
emergency 76
seperate system 6
drought 19
drowning hazard 9,27,53
drums 6,50,76,89
E
earthquake 2,35,53,77-89,89
earthquake loads 91
ecological design.See design, ecological
economics.See cost
Eden 88
electricity 1
dependence 89
electric heater 74
electrolytic corrosion 42,43
electronic level indicator 70-89
embankment 26
emergency
reserve 35,52,56,73
storage 75-89
energy
consumption 6
thermal 2
engineer's stamp 52
engineering 53,77
EPDM 22,23,24,46,94
epoxy-coated rebar 57
epoxy-coated steel 47,94
erosion 24
Ethylene Propylene Diene Monomer.See EPDM
Evans, Ianto 13
evaporation 2,16,20,23,23-24,27
swimming pool 27
evaportranspiration, vs precipitation 20
excavation 101-107
expanded metal lath 92,113,114,117
F
failure 8
fecal matter 11,12.See also bacteria, pathogens
fences 78
ferrocement tanks 41,57
construction 95-120
experimental improvements 96
forms for 96
heavy-duty 107-120
light-duty 101-103
medium-duty 104
skill required 95-107
spherical 96
tank shape 38
ultra-light-duty 100-101
fiberglass (glass fiber-reinforced polyester) 32,46-47
footings for 49
field capacity 15,16
fill 48,60
fillet 92
filtration 10,66,124
fire 1,2,124
department 52
fighting 52,78-81
hoses 1,79-89
hydrant 2,35,52,55,73,79,80,81,83
reserve 34,56
resistant storage 77-89
safety 21
sprinklers 2,80-89,89
trucks 81-89
fish 21,22,24
in 26
nuisance 27
floating solids 8,62
float (level indicator) 69-89
float switch 71
float valve.See valve, float
flooding 2,24,25,53
hazard 52
plains 21
reduction 16
floor 48-49,55
concrete 38
conical 92,112
construction 105,109
dished 92,112
finishing 116
flexible 91
options 61
pouring 115-116
pumping 115
shape innovations 112
slab 113,115
sloped 60
stiff 91
strain 49
Thai jar 97-107
flow.See water/flow
foam injection 36,79,81-89
footings 48-49,102-107
Thai jar 96-107
forms.See concrete, forms
fossil fuels 3
foundation.See footings
fountain
hydroelectric 29
freeze protection 1,2,73-75
by burial 31
pond depth 24
frost heave 32,91
ft3/sec (cubic feet per second) 90
fungicides 39
G
gallons per inch 70-89
galvanized steel 8,41-42,56
corrosion.See rust
welded tank 64
with plastic membrane 47-48
galvanizing paint 56
gal (gallon) 90
Gambusia.See mosquito fish
garden hose 79
gasoline 78
gasses, disolved 11
gate valves.See valves, gate
generator 79
geology 18
glass 39
glass reinforced polyester (GRP).See fiberglass (glass fiber-reinforced polyester)
goals 1,4,5
goat bladders 48-50
gpm (gallons per minute) 90
grading 105
gravel (as footing) 48
gravity
flow 29,55,66
loads 91
gravity flow water systems 120
Greenpeace 45
greywater
storage 6
greywater systems
for runoff harvesting 16
grid 111
groundwater.See aquifers
gauge.See pressure gauge
gutters 42,65,80
H
hardness 12
hardware cloth 92,114,117
hazards 52-53
biological.See pathogens
liability.See liability
ha (hectare) 90
HDPE 46,76
cast into masonry 61
taste 46
toxicity/leaching 46
health department 52
heating
effects 10-11
heat loss 54
high density polyethylene.See HDPE
hilltops 31
hog-ring pliers 107
pnuematic 107,117
homeowners' association 52
hoops 113
spacing 114
stress 92-96,113
hot springs 54
drain 62
hot tubs 75,81
hot water storage 54,75
Huehuecoyotl Eco Village 11,16,25,83-84
hurricanes 2,77-89
hydrant.See fire hydrant
hydroelectric 14,16,83-84
battery 2
pressure for 29
hydrogen sulfide 67
I
ice-skating 21
ice loads 91
indoor supply plumbing
copper 42
infiltration 15
basins 7,19,21
coefficient 19
galley 87
inlet 12,55,55-56,58
aerator 10,67
combined with outlet 66-67,67
diffuser 67-68
float 73
float valve.See valves, float
hidden 104
in roof 56
welded 56
insulation 74
insurance 52
Intermediate Technology Development Group 96,101
iron 12,67
irrigation 6,7,16
covering peaks 34
drip 7
storage in soil for 15-16
K
Kemnitzer, Paul 107,120
kitchen sinks 30
kPa (kilopascal) 90
L
ladder 9,53,56,57
built-in 117
Lake Cachuma 24
landslides 31,53
lath.See expanded metal lath
laundry 7,75
leaching.See toxins, leaching
lead 39
based paint 9
glaze 44
leaks 9,23,27,56,61,68
in wood tanks 45
leather 48-50
legal requirements 1,2,5,52,67
firefighting 36,78
levees 22,24,25
construction 25
cross section 26
level indicators 69-71
lexan.See polycarbonate/ lexan (PC #7-other)
liability 5,21,53
lid 9
removable 27
lifestyle accommodation 4
lightning 77
lights 115
lime 12
livestock 7,21,24,26
loads.See structural loads
locks 78
long-term storage 76
Los Angeles 89
Low-Density Polyethylene (LDPE #4) 94
low pressure.See pressure, low
lpm (liters per minute) 90
L (liter) 90
M
m3/day (cubic meters per day) 90
m3 (cubic meter) 90
manganese 67
manhole.See access (tank)
marine plywood 45
market culture 3,5
Maruata 16-18
masonry 60
masonry in and over plastic 47
materials 28,39-48
efficiency 36,38
toxicity 12
to avoid 39
membrane 92
meter 66
Mexico 83,93
microclimate 21,74
mold.See concrete, forms
mold-release agents 39
mosquito
screened 55
mosquitoes 9,22,27,52,63,65
fish 27,124
trap 52
multiple tanks 7,72
plumbing options 73
muskrats 25,27
m (meter) 90
N
Nalgene bottles 94
National Drinking Water Clearinghouse 120
National Fire Protection Association 120
National Testing Laboratories 120
natural pools 27
natural resources
waste 33
natural swimming pools 120
New York City 88-89
Nil 102
nitrates 20,23
non-modulating float valve 120
NSF 61 certified 39,46,47
cement 41
sealers 41
NTU 90
nutrients
and algae 27
in water 65
O
oak 45
odor 12
organic mater 9
outlet 9,12,35,56
curves 71
float 68
for pond 24
screen 68
overflow 9,25,52,55,62-65,71,73
critical 64
for pond 24
line 63
size 62
uncontrolled 9
oxygen 67
for fish 26
ozonation 2,10,71,76
P
paint 12
reflective 65
with zinc 41
pallet wrap 108
pasteurization 10,11
pathogens 10,12,13,53,72.See also bacteria
pebble tech 27
perched aquifer 18
perfectionism 109
performance standard 4,5
inflation 4
permeation 11,53,76,78-89
permit.See legal requirements
pesticides 13
in aquifers 18
PETE.See Polyethylene Terephthalate (PETE or PET #1)
pH 12,26
pipe 29
abandoned 12
nipples 8
size 1
supply
size 32
wrap 109
planes 93
plants.See irrigation
plaster 113
color 119
curing 119
in tension 92
mixer 108,118
plasticizers 39
plastics 65
American Plastic Council 45
health & ecological issues 94
membranes, coatings and bladders 48
tanks
drain retrofit 60-65
footings for 49
tank material 45-46
tank shape 38
taste 46,76
plumbing 11
code 52
for easy changes 8
point loads 91.See loads, point
polyamide epoxy.See epoxy
Polycarbonate/ Lexan (PC #7-other) 76,94
polyethylene 54
septic tanks 32
Polyethylene Terephthalate (PETE or PET #1) 46,76,94
Polypropylene (PP #5) 94
20-27,81
clay core 25
combination 22
cost 25
depth 24
duck 6
embankment 22
excavated 22
failure 22,25
liners 24
living 21,22
locating 21
runoff harvesting 21,22
shape 24
size 24
storage 21,22,23
turn over 24
types 21
wall slope 24
weeds 24
Popocatepetl 93
population 7
pot growers 51
power outage 35
pressure 6,8,29,36,91
for different applications 30
gauge 66
as remote level indicator 70-89
inward, from burial 32
loss in tank 33
low 29
maximum 29
spike 69
switch 71
tanks 29,30,38,54
very low 87-88
Principles of Ecological Design 124
progress, true 3
psi (pounds per square inch) 90
pump 30,56,88,89
buried tanks 31
for fire 79
for pressure tank 54
pumping 1,2,3,6,15,19,20
downhill (pet peeve) 32
energy use 30
pump control 71
purification.See treatment
PVC 8,45,46,51
in sunlight 9,39
pipe 14
R
raccoons 76
radial with hoops 111,116
radio links 29,71
rainwater 7,27,76
cistern under an office 64
fate of 15
gutters.See gutters
harvesting 12,72,83,88,96
Huehuecoyotl 83
tank for 101
infiltration 16
Rainwater Catchment Systems for Domestic Supply (book) 120
Rainwater Harvesting & Runoff Management 7,15,19,21,50,84,124.See also runoff
rats 9,65,76
rebar 92,113
hickey 107
joining 114
overlap 114
spacing and size 92
welding 114
recycling 8
redwood 27,45,77,92
red cedar 39
regulations i
reliability 8
repair 8
reserve.See emergency, reserve
resource use 3
riprap 25
river 81
rocks 11
tank shape 38
rock and mortar.See stone tanks
roofs 50,116-117
cave-in 118
center pole 117
conical 38,50,57,92
domed 38,50,91,92,93,116
construction 102-107
flat 50
grid 117
hexagonal 50
water harvesting 50
roots 49,77-89
as pumps 15
rope 53
runoff 7,15,20,21,23,25,56,83
rust 41,48,58,63
S
sacred spots 31
safety factor 92
salt
flushing 7
sand
filter 72,86
silica 119
sand filters 120
San Juan Island 72
screed 116
security 31
and tank size 32,33
standard 4
sediment 9
septic conditions 12
septic tank 10,44
outlets 63
plastic 32
set-aside.See reserve;See also emergency, reserve
settleable solids 86
settling 2,8,10,11,73
inlet diffuser for 67
sewage 10
in aquifers 18
shade 65
shape 36-38
for burial 32
graphical overview 36
rectangular 9,36
rock-like 117
sphere 32,36,38
square 36
structural effect 93
shear force 92,113
shower 1
shut-off valve.See valve/shut-off
silver solder 54
sinkholes 19
siphon 55
site
prep 109
walk-in only 109
siting 28-32
size
structural effect 93-96
sizing 32-36,44
for firefighting 36
for intermittent production 35
for interruptions in supply 35
for limited supply 34
skimmer 27
skinny-dipping 78
slab.See floors, slab
slope
stability 29,31
steep 53
sludge 58
small containers 76
smell 12
snow load 93
soil
loads 91
report 52
storage in 15-16,25
vs aquifers 15
solar
greenhouse 2
heaters 75
source direct 14-15,85,85-87
specific heat 2
spillways 25,64
spill point 55
springs 1,2,9,12,14,16,18,22,23,34,66,85
stainless steel 42,54
standpipes 79
steel
reinforcing 95
tanks 48
tank shape 38
Stinson Beach 15
stone tanks 43
storage .See , storage
stress
uniform 93
structural loads 53,91-93,91-96
buried 31
collapse 53
considerations 91-93
efficiency 36
point 116
stucco.See plaster
subsurface irrigation.See irrigation/subsurface
suburban house 89
sulphur 12
sun, on tanks 9
sunscreen 47,65
by burial 31
supply 66.See water/supply
surface area, formulas for 90
Surface Water Treatment Rule 120
suspended solids.See turbidity;See also floating solids;See also settlable solids
swamp coolers 2
swimming 22,124
holes 11
pools 27,75,81,89
aboveground 27,51
variable level 27
swing joint 80
system modes 28
T
tanks
cleaning 58,59,60
coatings
toxins in 39
cost.See cost
forces on.See structural loads
galvanized.See galvanized steel
multiple.See multiple tanks
on roof 29
open 27
painting.See paint
shape.See shape
siting.See siting
sizing.See sizing
Tank Talk Newsletter 120
tannins 22
tap station 98
taste 12
temperature 12,65
of buried storage 31
tension force 92,93
Thai jar 96-98
thermal mass.See specific heat
thermal storage 1,2
thermos 54
Thoroughseal 106,116,119
toilet 7
flushing 7
tank 75
tools 107-108
torque block 59
tote bins 51
tower.See water, towers
toxins 7,9,53,78
leaching 11,12,53,76
PVC 39
threat to aquifers 20
transporting water 54-58
trash cans 39
treatment 2,73,124
biological 27
residual 10
trees 77-89
triangles 93
trihalomethanes 9,10
tunnel vision 3,5
turbidity 7,12,67.See also floating solids;See also settlable solids
and fish 26
turbulence 71
U
ultraviolet light 10
underground river 17-18
union 56
units.See measurements
V
vacuum breaker 25
valves
ball 62
check 55,56,63
float 55,66,71
gate 69
shut-off 55,56,61
vandalism 78
variable height outlet 68
vector control 52
vent 55,65
vermin 27
vernal pools 22
volume, formulas for 90
W
walls 91,102-107
floor joint to 113
structural loads 92
thickness 92
washing machine 7
water
age 12
bottled, survey 12
color 12
corrosive 12
demand
forcast 7
flow 1
hazards.See hazards
level 105,107
pressure.See pressure
protecting 77
quality 1,2,4,12,16,83
changes 9-13
guidelines for different uses 7
improving 10
of 20,23
separate handling 6-7
testing 12-16
quantity 5
running 6
security 1,1-2
shortage 1,19
softness 7,12
stagnant 12
still 6
stored energy 2
supply chain 1
taste 7
temperature 12
towers 29,38,53,54,66,77
safety 30
use
covering peaks 33-34
hourly 34
peaks 1
per capita 6
waterbed bladder 39,48
Watermaster 120
watershed 16,18,20,25
area for 23
water age 120
water hammer air cushions 68,69
Water Quality Testing Procedures and Information Packet 124
Water Storage Extras 124
weather station data 120
welded steel 60
wire mesh 109
wells 9,17,18,55,66,82.See also aquifers
artesian 16,18
contamination 55
horizontal 16,87
low yield 34
wildlife 22
and 26
habitat 21
Willard 107
wind.See hurricanes
wind loads 91
wings (for rain harvesting) 116
wood (tank material) 45
Y
yucca stalk 61
Z
zinc 42
zoning 52
SeeWater Storage (book)main page
Chapter 1: Thinking About Water To achieve your design goals water system, it is helpful to know what your goals are. first order of business is to consider: Why Store Water? Nearly all water systems include some form of storage, most commonly tank. Storage can be used to: cover peaks in demand smooth out variations in supply provide water security in case of supply interruptions or disaster save your home from fire meet legal requirements improve water quality provide thermal storage freeze protection enable smaller pipe to serve distant source We're going to consider each of these reasons to store water, then look at design principles to help you frame goals your project. Cover Peaks in Demand most common function of water storage is to cover short-term use flows that are greater than flow of water source. example, tiny, one gallon-per-minute spring supplies 1440 gallons day. This is several times more than most homes use in day. However, almost every fixture in home consumes water at faster rate than 1 gpm while it is turned on. Even low-flow shower head uses about 1.5 gpm.m By using water stored in tank, you can supply water to shower faster than it is flowing from spring. On completing shower, water will be coming in faster than it is going out, tank level will rise back up. If you had 10,000 gal tank, you could run 100 gpm fire hose--creating kind of blast used to bowl over hostile crowds--on stored water from this tiny spring, hour half! Hopefully fire would be out by then, as tank would take several days to refill. Smooth Out Variations in Supply In some circumstances, your storage needs will be affected by variations in water supply. instance, if supply is rainwater, you will need enough storage to make it through intervals between rainfalls. six-month, rainless dry season requires heck of lot more storage than most common kind of variable supply-- well pump that cycles on off. If you have well that taps stored groundwater, tank will save wear tear on your pump, because pump won't have to switch on off every time you open tap. Provide Water Security in Case of Supply Interruptions or Disaster In many places, water supply chain from source to tap is long made of many delicate links. If cow steps on supply line, pump breaks, wire works loose, electricity goes out, city misplaces your check, or there is natural disaster, your water flow could stop. By locating your storage as few chain links away as possible from your use point, large measure of security is added: In case of earthquake, hurricane, flood, etc., storage can be slowly emptied to meet essential needs until service is restored. If your well or electrical pump goes out, or your spring lines wash out, storage you have water until you can get it fixed. Save Your Home from Fire Designing system to be effective combating fire can change its specifications radically. To put out fire, your stored water needs to be available at flow rate many times greater than normal. (If you want your system to have this capability, see Systems Firefighting, p. 78.) Meet Legal Requirements Sometimes you may be required to install water storage simply to meet legal requirement. On other hand, you may be able to trade increased water storage slack on different legal requirement. example, if you provide large amount of water good pressure that is reserved fire emergency, sprinkler system, /or hydrant, fire department might allow you to build narrower driveway smaller turnaround further from house than they would otherwise--thereby saving you fortune. Improve Water Quality water coming out of properly designed tank can be of significantly higher quality than water that goes into it. This is mostly due to attrition settling (see Ways to Improve Water Quality in Storage, p. 10). Add ozonator, tank becomes substantial treatment step (see Ozonator, p. 71). Provide Thermal Storage Freeze Protection Water has higher specific heat--stores more thermal energy per unit of weight--than any other common material. large thermal mass of water stored within solar greenhouse or home can help to keep it cooler in day warmer at night. Also, as water changes to ice, it radiates tremendous amount of stored energy. Imagine how much gas it would take to melt water tank-sized ice cube; water freezes, it releases this same amount of energy. This is why irrigating frost protection is effective. stored energy in water can prevent water tank or nearby components from freezing (though in coldest climates this may not be sufficient--see Freeze Protection, p. 73). Evaporation consumes even more energy, is why swamp coolers cooling towers are effective. Water is also effective heat transfer medium. Finally, in rare instances it can be economical to use elevated water storage as Ïbattery," from electricity is extracted by running it through hydroelectric turbine. Enable Smaller Pipe to Serve Distant Source If flow of your source exceeds peak demand, you can connect to it directly without storage. However, if source is distant, it may be cheaper to run small pipe to nearby storage, big pipe from there to use point. small pipe would be sized to average use, big pipe to peak use. savings in materials labor from running smaller pipe over most of distance can often pay storage then some. Design Principles This book sees water storage through lens of ecological systems design-- view that is both global finely detailed. You don't need to share this view to value utility of material in this book or benefit from its application. However, ecological design approach offers so much advantage so many pressing issues, feel compelled to take moment to look at design of systems before diving into details of water storage. (If you are not in mood design philosophy, please skip ahead to Separate Handling Different Qualities of Water, p. 6.) Ecological Systems Design has been my day job since 1982. My focus since 1989 has been design of water wastewater systems. 've designed, built, studied water systems in twenty countries, covering many applications, in wide range of natural cultural conditions. designed my own major in Ecological Systems Design, completed at UC Berkeley. However, my most important insights have occurred in countless rugged miles 've logged exploring extraordinary wild water systems. 've become very aware of how water quality changes as it moves through natural engineered systems. This, my experience testing water have led to many realizations that have influenced designs in this book. My work-- life--are inspired by what call Principles of Ecological Design.1 In brief, to design ecologically, follow these principles: Transcend market culture. main obstacles to living nature are cultural, not technical or economic. Much of American culture has been designed by marketeers, is diametrically opposed to living cheaply ecologically. Follow nature's example. Natural water systems are vastly more sophisticated elegant than artificial ones. Pay them heed--they are gold standard. Intervene as little as possible. Choose inherently simplest solution, then implement it as well as possible. Remember that maintenance increases number of parts, that any moving mechanical part is itself many parts. Understand that context is everything. context must be known in order to determine if design is Ïgood" or not. There are no universal solutions. There are approaches patterns that can be applied to generate optimum solution in variety of contexts. Nature provides diverse solutions to all problems; she never repeats. Every branch of tree is different shape that fits its purpose exactly. Overcome tunnel vision. Design global, yet detailed view. market economy tends to promote tunnel vision, using exponentially increasing amount of money resources to get higher performance on narrow set of parameters, while whole withers. Use appropriate technology. Cleverly matching level of technology power of your tools to task at hand is cheaper, healthier, lower impact, more enjoyable--yet ultimately more powerful than any single solution. Practice moderate efficient resource use. Fossil fuels electricity have severed connection between energy source consumer. One thin pair of wires can silently channel unbelievable amount of energy to pump deep underground without creating ripple of awareness. This has enabled our relationship energy to skew way out of scale. (Consider how you'd conserve if you were walking down forty flights of stairs carrying water back up in buckets.) Empower users' awareness creativity. Design monitoring adjustment. We kid ourselves that our artifacts are immortal but they all fail time. Nature allows failures, using information to improve her designs building in flexibility changing conditions. Make true progress. Most of what is commonly called Ïprogress" is relocation of problems out of sight in space or time. True progress actually solves problems. Water System Design Here's what general ecological design principles look like applied to design of water systems: Minimize overall negative impact on natural social systems. easy way to do this is to spend as little money use as little water as possible. Create positive impacts-- example, by slowly releasing stored water to ecosystem during dry season. Leave as much of water work as possible to nature. Divert water just after evaporation or soil has naturally purified it so that it requires no further treatment. Divert water higher than point of storage points of use if possible, -- Conserve pressure in plumbing so that minimal or no pumping is required. Use adequately, but not excessively, sized pipe to reduce friction loss it matters, use pipe that's as small as possible friction loss doesn't matter. Design to extract benefit from other attributes of your water, e.g., nutrients, softness, temperature, pressure. Rigorously confine materials that are incompatible natural cycles (such as motor oil solvents) to their own industrial cycles. Add to water only cleaning products materials that biodegrade into plant nutrients or non-toxins. Add these materials in order that lets water cascade through multiple uses, from those that require cleanest water to those that tolerate dirtiest. Distribute nutrient-laden final effluent to topsoil on-site purification/ reuse. It is worth reflecting on these principles before you spend thousands of dollars on your water system. All design is art of trade-off. cost-benefit curve most design parameters shows diminishing returns. It goes up steeply at first, then levels off. However, trade-offs external costs continue to increase. If you push too far trying to maximize few parameters at expense of everything else, you will wind up less less total benefit. too narrow or fuzzy view, myopic push to maximize parameters in sight will inevitably compromise parameters that are not seen (see Tunnel Vision, at right). It is relatively easy to save water by wasting energy, or to save water energy by wasting materials money. It is relatively hard to make overall improvement. easiest ways to achieve this are to: get stay clear on big picture goals change specifications so that full range of effects are explicitly considered improve fit between subsystems decide what is least necessary cut it out make some lifestyle accommodation Performance Security Standard water system's performance security standard can be expressed as percentage of time system is Ïup." If your water is on nine days in ten, that's 90%. If your system is down three days year, that is performance security standard of 99%. If your water were off only one day every ten years, that would be 99.97% standard. performance security standard is relatively invisible design parameter. It is almost never discussed openly, even though it can influence design more than just about anything. Here in America, culture is fear-based, business interests dictate government policy, there tends to be runaway inflation in performance security standards. Our grandparents carried water in buckets from open well in backyard, yet we fear we'll die if tap isn't always capable of delivering way more sterile water than we need, at high pressure. my clients, always haul performance security standard out in open conscious consideration. You don't want to design having water 100% of time. To go from having water 95% of time to 98%, to 99%, to 99.5%, requires roughly doubling of expense environmental impact each increase. You need to take into account consequences of insufficient storage, your emergency supply options, environmental impacts, your budget to determine appropriate performance security standard your system. If it doesn't really matter much if you run out of water, why spend fortune on storage? Then again, if you have kidney dialysis machine or some other critical application, obviously you'll want to set security standard higher. Running Water People, Still Water People Worldwide, people who have pressurized water on tap use about hundred gallons day per capita. People who carry water use about ten gallons day to accomplish much same tasks. Most of difference is waste. It is easier to let tap run than to turn it on off. In contrast, still water just sits there serenely until you scoop it up. On typical construction site in industrialized country there are hoses spray nozzles--push lever water blasts out. In non-industrialized societies, there are typically couple of big drums buckets of water construction use. Since almost none of construction water needs to be clean, water is cascaded through various uses. example, tools that have been used adobe or cement are cleaned in drum, muddy (or cement-y) water is then reused to make adobe (or concrete). Water washing hands is scooped out of Ïclean" construction water drum, into bucket, then dumped into Ïmuddy" drum it is dirty. non-industrialized method has advantages both consumption disposal. water consumption ( energy consumption, if water is pumped) is fraction as much as in industrialized scenario. Also, instead of leaving giant toxic puddle of cement water, all cement water is incorporated into masonry work. (We are working on development of hybrid plumbing systems that combine convenience of pressurized water efficiency aesthetic benefits of still water.) Separate Handling Different Qualities of Water In many contexts it makes sense to use different qualities of water different purposes. Depending on water use, specifications (including those storage) may be quite different (see Table 1). If more than one type of water needs storage, storage will have to be separate. As kid, irrigated my first garden water siphoned from child's swimming pool that was used as duck pond. Clear well water went into pond, after week's storage, drew out thick, chunky, pea soup-looking water. garden, duck poop water was better than potable water. Drinking water requires most stringent specifications source, storage, security, but is used in smallest quantity. You might be able to make your life much easier by making separate system separate storage drinking water. ( example, see Creek Direct Sand Filter, p. 85.) Irrigation water has least stringent specifications water quality, storage, security, is typically used in largest quantity. It can be stored separately in inexpensive, high-capacity storage such as soil, ponds, or aquifers. Water irrigating fruit trees shrubs can be of lower bacteriological quality than water used irrigating vegetables consumed raw. Greywater (household washwater) should not be stored in tank more than 24 hours. It is best to route it to soil as it is generated store it there. (See our book Create Oasis Greywater/ Common Mistakes Preferred Practices.2) Rainwater from roofs is especially suited hair washing, laundry, flushing salts from soil, due to its extreme softness. In old days, inns would have pitcher of spring water drinking, separate basin of rainwater washing. It is prudent to plumb rainwater downspouts to your greywater distribution or irrigation system (if you have one) so soft rainwater can flush irrigation salts from soil, as it soaks in recharges groundwater. It is not necessary to have storage to do this; it is actually most effective to do it while it is raining. If you have separate rainwater harvesting tank, you can plumb it to supply washing machine bathtub, any extra going to toilet overflow to salt flushing. (See our forthcoming book Rainwater Harvesting Runoff Management.3) Runoff water is generally suitable only irrigation, flushing salts from soil, or groundwater recharge. (See Aquifers, p. 16, Rainwater Harvesting Runoff Management.) Table 1: Different Water Qualities Different Uses Contamination limits Use Fecal bacteria per 100 ml Turbidity Toxins Notes Drinking water sensitive humans 0 Almost none Almost none Needs to taste good Well-direct groundwater recharge 0 Almost none Almost none Drinking water resistant humans 10 Low Almost none Needs to taste good Drinking water livestock 300 Moderate Almost none Dishwashing water 300 Moderate Low Bathing water 300 Moderate Low Laundry water 1,000 Moderate Moderate Best if low in calcium, magnesium Toilet flushing water 1,000 Doesn't matter Moderate Irrigation of annual vegetables 1,000 Doesn't matter Moderate Groundwater recharge through mulch-filled infiltration basins 3,000 Doesn't matter Moderate Irrigation of fruit trees 3,000 Doesn't matter Moderate Subsurface irrigation 10,000,000,000 Doesn't matter Moderate Irrigation of non-fruit trees 3,000 Doesn't matter Matters least Drip irrigation 3,000 Almost none Moderate Will clog if it has lots of solids Warning: These figures are based on my observations of what is working in practice, depart radically from legal standards at points--follow them at your own risk. Our other water books articles have more information about different qualities of water different purposes.4 Design Horizon Water supply systems should typically be designed built 15- to 25-year life span. biggest variable over this time is often population. Population determines needed capacity tanks, pipe sizes, etc. If long-range water demands cannot be accurately forecast, shorter design span can be used. Note that providing abundant water tends to make population bloom, exerting feedback effect. One of best ways to account changes in future storage needs is to provide addition of more storage later-- example, in additional tanks (see Figure 26, Multi-Tank Plumbing Options, p. 73). Instead of putting your first tank smack in middle of one area tanks could go, put it to one side. Later, you'll be able to add more tanks next to it if necessary. Design Failure, Design Change Another key to good water system design is to consider how components will age, what to do they fail. Every piece of system is going to fail someday. Ask yourself what is going to happen it does. Will its failure be dramatic, or mundane? How long will it take to fail? Can failed part be accessed cleaning, repair, replacement, reuse, or recycling? Good design makes it easy to change system--to add another tank, new connection, valve, etc. As you're making original installation, picture your future self having to come back to expand or repair system, make it easy to do so. Take look at Figure 18, Drain Options (p. 61), example. You'll notice that sections of PVC pipe between fittings are long enough that you could saw through them in middle still have enough pipe on both sides to insert replacement valve, insert tee to another pipe line, or make some other change or repair without having to throw anything away. If fittings were all glued together Ïhub to hub," no exposed pipe between them, to change anything you'd have to throw everything away. Likewise, galvanized pipe nipples in Figure 18, Drain Options (p. 61) are smallest size that still allows pipe wrench to grip pipe. Shorter nipples are one-use; to get them out you've got to grip them wrench on threads, wrecks them. Stuff in Water Ends Up One key to good water system design is to focus less on water. Sure, water is significant. However, there is tendency to think that water is taken care of, design is done. Most designs fail to account adequately other stuff in water: materials that sink to bottom materials that float on surface materials that dissolve into or out of water air that is displaced by water water-seeking critters that crawl or fly into system Take care of other stuff, water will just about take care of itself. Moreover, your system will deliver higher-quality water more reliably, be less quirky, last longer. This is especially true if your design parameters are extreme in any way: lots of sediment floating crud, very low pressure, barely enough water, wild fluctuations in supply or use, etc. How do you design other stuff? It's easy: Not just water, but all stuff that comes along it ( air it displaces) have to go somewhere. Simply ask yourself, Ï are air, sand, leaves, rust chunks, mineral deposits, spiders, frogs, mosquitoes going to end up in my system?" Consider different design scenarios you'll find best overall disposition of water its companions. (See Figure 2, Common Storage Problems, p. 9.) What Do You Have? What Can You Find? In practice, people are likely to use tank they already have, or one that's sitting in boneyard down street, or tank that can be purchased easily inexpensively. This is true even if tank is considerably smaller or bigger, of another material, or otherwise out of sync theoretical ideal. Cheap easy weigh very heavily in practical terms. Salvage st