c. Water

A critical resource and especially in our dry subtropical climate, this is also the least developed part of the design to date, being the easiest part to make ‘type one errors’ as it involves some building (water-collection + ferrocement tanks).

These are the sub-headings of this section, click to go to each page (also in main menu):

Finca Luna

Fertility

Water

Buildings

People

We need to do a lot more observation and also accumulation of resources in order to do a good and lasting system that conserves and collects as much rainwater as possible, makes optimal use of irrigation and domestic water usage, retains as much humidity in the soil as possible and stores or directs it to the most fruitful places.

Water in the Ground

This is the best place to store water (cheapest but also particularly in arid lands, the safest place) and part of this system already works very well as testified by much lush vegetation appears soon after the first rains in october-november and lasts until may-june.

The best way to retain this humidity is to plant a lot more trees both to take advantage of the deeper storage of water, to shade the surface from evaporation and produce a mulch on site to also hold water.

Slowly infact we are planting trees with swales all over the finca, starting with the most urgently needed ones (eg. wind brakes).

We are doing this slowy because on the the piped water supply is limited at present (until we repair the tank and buy water shares) and we want each planted tree to be waterd adeguately thoughout the year.

The gray water from the shower is retained as much as possible near the surface by a large ‘sponge’ of straw, old clothes, cardboard, etc. and a surrounding planting of banana, sweet potato, passionfruit and other plants. This works well.

Water Tanks

an existing 5x5x6m stone water tank at the bottom boundary of the finca stores the gallery water that is piped from the mountain and which is one of the great luxuries of living here: ‘water communites’ distribute ‘water rights’ and we currenty rent part of one (1 derecho = 1 litre per minute) and plan to buy one as soon as the tank is repaired (and so become shareholders of our local water community).

We also have domestic water (chlorinated) piped in and metered, but the spring water is much better drinking quality.

We could collect the rainwater from roofs and paved areas if we had more tank space and also we need tanks uphill to make the whole system work better.

However, as the original finca already had this in place but now is divided into 4 lots (we have one of them), it seems to make sense to also wait and see if co-operatively-minded folk buy the other lots in the future, as the various tanks would complement each other perfectly.

In the meantime, we are exploring a possible innovation using the ferrocement technique which was much used on the island in the 50s for very large water tanks.

The idea is to replace the stone supporting walls of some of the terraces (where these are falling down) with small cilindrical ferrocement tanks (1,2m diam. x 2.2m high).

This could be tried out progressively as there are only a few places where the terrace walls need repair, but we haven´t (so far) been successful in finding ferrocement construction experts to learn from (so we’ll probably do some experimentation ourselves soon).