Small scale rain water harvesting and groundwater recharge through earthworks.
Our dream is to transform our homestead into an example of good rain water harvesting practices. Our plot is situated in a lightly sloping, rural landscape and has a size of 3000m2Â We have about a thousand square meters (1000m2) of paved road sitting on the West and upslope of us, perhaps more if you count the houses and church that evacuate their roof water onto the road. When it rains this road turns into a little stream. I have calculated that anywhere between 400 and 600.000 liters of water run past our land every year on an average rainfall. I hope to capture as much ofÂ that water as possible and use it to bring our landscape into abundance, produce food and recharge the aquifer. Besides the benefit to our own lives and those of our children and grandchildren, we aim to to use this site as an example site for a variety of different earthworks that are useful in harvesting rainwater. In short, we aim for the mutually supportive functions of biodiversity, water abundance and spreading knowledge on water harvesting.
To give a bit of a sense of the scale, this is what the street looks like in a ‘small’ storm. In this case about 60.000 liters passed by in 24 hours.
The main goal is to maximize the amount of storages for the water in the landscape.
In other words, to have a wide variety of ways for the water to be captured; like trees or other vegetation, animals, tanks, ponds and of course in the soil. Anything that will keep the water around and help create more organic matter in the soil. Besides the water storage options we will try and minimize the evaporation rates by planting windbreaks and shading the soil. This will create a resilient network of elements with beneficial relationships. Not only will this place end up looking like a food producing water-park, but it will also perform as an education site for planting the rain.
Several different ways of harvesting, cleaning and storing water are being considered. In an ideal situation we will implement a version of all of these and more, but we are of course limited by time and money. We will most likely implement the major earthworks in one big go and then sequentially implement the other parts when time and energy permits. Here are someÂ of the ideas.
– Road catchment drain and sediment trap.
– Gravel and reed pre-filter.
– Contour trenches for slowing, spreading and sinking the water. To be planted with fruit trees (Also called swales, video introduction here).
– Shallow well on the downhill side of the swales. It will only be used minimally and to test how quick the water table recovers after installing the swales.
– Different ways of managing the overflow from the swales. Level sill spillway, sluice-gate, overflow pipes to direct the water, etc.
– Large roofwater storage for indoor use.
– Vertical helophyte filter, filtering black water. Overflows into the next item.
– Small scale artificial stream planted with habitat plants. Overflows into the wildlife pond.
– Wildlife pond. Functions to support as much biodiversity as possible. Clear clean water.
– Duck / fish pond / water storage dam. High nutrient load. To be used for fertigation.
– Possibly some small scale aquaponics.
– Water oriented playground. For kids to experiment with weirs, dams, sand and of course, water.
– Large infiltration basins around hardscape and important trees.
– Net and pan watering system around olive trees.
– Educate people through tours and signs the diversity of relationships between all of these systems.
Other important functions.
- Water treatment
We currently have one vothros (cesspit) that collects all of the waste water we produce. We also have the vacation house of the cousins to the North of us that could possibly be harvested. The vothros needs to go as it is polluting the water table. We want to design and use a system that recuperates as much household water as possible whilst composting the solid waste. Both grey water and treated black water will be used in the garden for ornamental plants and fruit trees.
- Small scale alley cropping
Utilizing windrows of trees on contour and a specific species selection, a system of alley cropping will be developed for rows of annual crops.
- Home veggie garden
A small scale area of about 200m2 for home food production, utilizing a movable chicken tractor and localized mulch production.
- Research into earth bermed buildings in the Greek climate.
Earth is an excellent medium for regulating indoor temperatures. The average underground temperature at 80cm depth lies between 15 and 18 degrees. It will be very useful to research the use of modern day materials in building above-ground homes covered in earth. Above ground, because underground homes are almost always affected by soil moisture. Imagine a Greek version of a hobbit home ^_^