Lecture 4 - Water Flashcards
1
Q
Water cycle
A
- water evaporating from the oceans
- cloud formation
- once clouds hit obstacles/change in pressure, they will rain off
- snow melts from the top of the mountains
- the lower the water flows down from the mountain the more it gets naturally slowed down and the more the density of life rises
- these waterstreams coming from the mountains will turn to rivers above the ground or
- into underground streams that turn to springs/lakes or
- will penetrate deeper and become ground water
- brackish water is especially fertile (edge)
2
Q
Watershed
A
- all of the land that drains surface water (rainfall) into the nearest body of water
- everyone below us in the watershed will be directly affected by our decisions
- we have to build systems that will purify, store, use, cycle and clean the water before it leaves the whole system
- water can be an important tool to cool, hydrate and regenerate an area
- watersheds form a dentritic pattern
3
Q
Water storages
A
- landscape (ponds)
- soil (organic material soking up the water)
- plants
- tanks
4
Q
Ponds general rules
A
- if you do it by yourself for the first time, do it without big machines
- for dangerous ponds (highest water catchment) get expertise
- innoculate your pond with a bucket from a healthy existing pond
5
Q
Dam types
A
- valley dams require lot of work and need to be done right because they have to withstand lot of fast water
- gully dam: across depression or stream
- hillside dam: catchment off a hill, usually near to the bottom, if its not high enough, can’t use the gravity power
- saddle dam: on top of the hill, needs dams and spillways on both sides, very high, lot of energy
- ridgepoint dam: good for wildlife, less suited for irrigiation
- keypoint dam: at keypoint, within a valley where the waterflow naturally slows
- contour dam: runs on contour line, makes sense in flat areas
- gabion dams: lets through water (but slows it), holds back dibris (Geröll)
6
Q
Casing a spring
A
- find a spring
- go back to where the spring comes out
- dig down carefully to the next soil layer
- install a pipe with the right size
- make a gravel tunnel that you then seal completely with clay, that will direct the water fully into the pipe
- you now have a pipe of clean water (boom)
- test the water and then use it accordingly
7
Q
Water slowing
A
- slow (through earthwork and dams)
- soak (ponds, area around dams, where the water has been slowed down)
- clean (filtration through aerobic, anaerobic microrganisms + plants)
- store (keep harmful bacteria from growing, make sure no water is lost through evaporation)
8
Q
Building dams
A
- think about dam evaporation
- find a suitable site: look for depression and keypoint design
- wall : caught water ratio, have more value and invest least energy (for wall building here)
- reroute water to area where animals can reach it without destroying the dams
- silt trap: above pond to filter out sand, silt and clay
- do research before to find out if there a sewage, water, electricity, etc. lines
9
Q
Water Catchment
A
- calculate the whole water catchment of your property
- area (m2) x amount of precipitation (ml)
- calculate the runoff then
- water catchment x runoff coefficient (depends on type of soil, vegetation and slope)
*
10
Q
Keyway (Aquafuge, Core)
A
- impermermeable layer in the middle of the dam
- otherwise it will be muddy mess, harder for plants to grow
- every dam has to have one, not negociable
- consists of clay (30-40%), is compacted and is centred
- go down and find impermeable layer to connect the keyway to
- ex: Holzer goes around his land to find clay layer in the soil within an depression (preferably) to build the dam
- small amounts of water will seep through, but very, very slowly
11
Q
Sealing a pond
A
- if possible let the water seep into the surroundings naturally, to give moisture to the area
- clay route: clear area, fill any holes with bentonite clay, pre-moisten, erode or till the area 40 - 45cm deep, mix in the clay while tilling, so you have 30 cm deep mix with clay, then roll and compress it (sheep roller or animals), make the compacted seal no less than 30cm thick for 3m water depth, increase if water is deeper
12
Q
Spillways
A
- must for big rain events
- create spillway that leads the water to a grassy, flat area, that will slow down the overflow into the next water catchment
- trickle pipe: a pipe that runs below the dam from upper to the lower catchment to regulate the water levels in both ponds and migitate heavy water falls
- trickle pipe has to be put in place when the dam is built
- when thunking about pond size, depth, etc. take clues from landcape, try to use least energy and design dam size accordlingy
13
Q
Seal a leaky pond
A
- gley biofilm, put in resinous plant material, let microorganism build a green, sticky material that will seal leakages
- using manure (from ducks) and animals trampling inside the pond (Holzer did this with pigs)
- however you have to understand each situation individually, might now work out tho
14
Q
Swales
A
- flat ditch on contour to allow water to move through here
- is also a water infiltration site
- on the lower sloped side of the swale we plant trees to fix the soil with their roots and give shade
- in the ditch we have non-compacted soil, can be build only with shovels
- powerful tool, but only if used correctly and where it makes sense
- clay soil: increase pressure to get the water to soak -> narrow, deeper swales
- sand soil: use shallow, wide swales
- test the swales first on a small scale, they might not work in your climate (too much water for the trees planted at the side of the swale can lead to too few nutrients)
- don’t put swales in ares of flooding, pastures
- design the swales so they can take all the water in and if not integrate overflow
15
Q
Building a swale
A
- use an A-frame to mark the outer lines of the swale
- dig the ditch and put the dug out soil on the lower side
- everytime we cut the soil, we need to regenerate it, here: plant seeds with strong roots that will hold the swale in place, mulch, add compost tea
- in drier areas swales can also function as diversion drains to ponds or tanks, as otherwise you enough water cannot be collected
- swales can also be sealedfor different usages
17
Q
Water Conservation Ethics
A
- keep your greywater clean from harsh chemical, detergents, etc.
- treat greywater through life (reed beds, microrganisms, biochar, etc.)
- use good cleaners (ecological, no harmful chemicals)
- use as few as possible (water and cleaners)
24
Q
Keyline design - zones
A
- Water catchment zone: most upper area, steeper, what happens here affects the whole watershed - usually forest or savanna trying to slow the water
- Water retention zone: slope break from steep to more gentle break, within this zone lays the keypoint (contour lines closer together until suddenly the are further apart)
- Irrigation zone: starts below the first keypoint pond and goes down all the way until the river, water can be distributed here through gravity
- Water reconstitution zone: maximize wildlife, build more water storages if needed and reforest with native and riperian species to create and maximize wildlife habitat
- Keyline: level elevation lines on the height of the keypoints, represents water level in keypoint pond
- first keypoint is often ideal place for a pond (if the soil allows it), as the water is stored on the highest point possible
- from the first keypoint pond you can move the overflow around the ridge up to the next keypoint pond below, and so on (slow and store water)
- ridge ponds are safer for water storage in case of a heavy rainfall event, as most of the water will still flow through the valley (overflow of the keypoint pond) not to the ridges
- keyline pattern cultivation lines: lines within the irrigation zone that have a slight slope off-contour from the valley towards the ridges, to slowly drift out water throughout a bigger surface in heavy-rain events
