Rainwater Harvesting at KBS

They say good farmers look after their land, and then their animals look after themselves. And, while this might be great in theory, when you’re dealing with heavy clay, steep hills and delicate native grasses, it’s much easier said, than done!

On top of these issues, the South East of Bulgaria is very obviously experiencing climate change on a significant scale. Over our 13-years in Srem, we’ve seen the cold snowy January’s and February’s all but vanish, replaced with only sporadic rain. In the first few years, we would often experience temperatures of minus 10 and 15, now it rarely goes below freezing and certainly not less than minus 5 for any length of time. While summers are now longer and hotter, (mid-June to end-September) with July and August days regularly reaching 38 plus degrees.

Examination of the local rainfall data shows that while the average annual rainfall has changed little over the past decade, the issue really centres around how it falls. Ten years-ago it used to rain in long reliable periods, (spring and autumn with decent prolonged showers and storms throughout the summer), now however, rain events are short and violent, and when they do occur, they hit baked, unabsorbent soils with rapid and aggresive run-off.

Rainwater Harvesting

KBS is located on a small hill, between two valleys, this means all of our grazing land sitting on relatively steep inclines. The soil is predominantly clay and the forage self-seeded native grassland. While this clearly isn’t ideal by any means, (but we like to look at the positives), it certainly does add great variety to the horses’ diet (and of course, walking up and down all those hills creates really good muscle). The big negatives however are; unabsorbent and often compacted ground, rapid water run-off and of course with it, we say, “bye bye,” to any top soil we might have generated.

To counteract the issues, we’ve trialled and implemented several permaculture inspired water harvesting and conservation structures. These include; keyline dams, permaculture swales, traditional terraces and roof rain water collection. Some of these have been operational for almost a decade, while some are much newer and still bedding in.

Keyline Water Dams
The primary KBS water source is our 100 plus year-old stone-lined well. For over a decade it has fed the house, the horses, all our building works and the gardens, (around around 600 litres per day in high summer, but significantly less in winter) yet, since we owned KBS, we’ve watched the well water level recede year on year.

Located on the south side of our property in the deepest part of the valley floor, the well is fed from water perculating down from our grazing lands in the valley to the north. The main aim of our Keyline work, was to slow all run-off down the valley and allow water to penetrate the ground and replenish our well.

This summer we created two small keyline dams along the valley floor to aid water absorption in the vicinity of the well. Clearly it is already having some impact as a recent large rain event, saw the water level increase well water levels by over three metres.

In addition, the dams were placed in shaded and tree covered areas to reduce any evaporation and where we know we have significant wildlife activity (thanks Wildlife Cam!), in the hope we can encourage even more animals to venture in.

Mulching
We’ve been experimenting with various types of mulch and the mulching process for several years now. Currently we are working with a mix of fresh manure and straw- straight from stable to field. One thing we have a lot of at KBS is horse manure, and while we know it makes excellent compost after a period of about two-years, in 2020 we began experimenting with a slightly less ‘vintage’ product.

We’ve been experimenting with a particular one acre paddock for over a year now. Initially we spread around 50 tones of cow manure compost obtained from a local farm. After this, we added a good covering of old and spoiled mountain hay (waste not want not!) And, this year we took approximately one-quarter of this prepared area and added a good covering of the fresh manure and straw mix. The basic premise being, as the ground won’t be grazed till early summer, the manure will have time to break down and nourish the soil, while the straw adds protection from heavy rain, sun and wind, plus retains and creates top soil and encourages plant growth.

We began spreading this fresh mix around mid-October (when there is significant dew and several rain events expected). The breakdown has been good and already, thanks to the mild temperatures so far this winter, we have seen better foliage growth and damper/more protected soil when we compare the sample with areas not yet mulched.

Terraces
This Autumn we added a small trial terraced vegetable garden on the steep back garden area. The sample area was ‘no-dig,’ (both from a permaculture perspective and also because the clay was so badly compacted and baked after the hot summer, it actually bent my brand new German-made gardening fork!)

For this small patch, we used breeze blocks as the retaining wall and back-filled with mature (2-3-year old) home-made compost to a depth of around 6 inches. The difference in water absorption was extraordinary.

Autumn planting consisted of carrots, lettuce, spinach, arugula, turnips, leeks and radish. All grew successfully, and the root vegetables showed no signs of being impeded by the clay soil beneath. Sample digging showed that the layers of absorbent and spongy compost had effectively softened the clay base below. Over time we expect that the nutrients and moisture from the compost will continue to seep through the clay an improve the clay base, although to what depth, we don’t really know.

With the success of the trial, we are now in the process of creating three significantly larger garden terraces which will also be backfilled with manure and compost to create our new vegetable garden.

Roof Rainwater Harvesting
With barns, shelters, sheds and balconies, KBS has significant square metres under roof, although until recently, these were not being utilized to their full potential. This summer we sourced three large UV treated rainwater collection barrels, (two cubic, three cubic and five cubic) to begin roof rain water harvesting.

As we have several ideas on how this can be best achieved, we are currently using temporary systems and only collecting from two sides of the house and the horses’ field shelter at present. We plan after one year in operation, using two temporary systems, they have been highly effective. In fact so much so, the recent rain event earlier in January saw our three-cubic metre tank fill and then over flow.

The Swales
Ten years ago we added swales to our hilly backgarden area, the initial aim was to get more water to the orchard trees and slow water run-off towards the back of the house which was causing top soil run off to build up behind the house and causing damp.

However, with the horses having escaped numerous times over the years to ‘prune’ the trees, the orchard is underwhelming to say the least, yet the swales have proved their worth, time and time again. Firstly, top soil has stopped moving and there is zero new build-up behind the house. Monitoring via Google Maps, has shown that through July and August, while the land around us becomes parched and brown, the swales have kept the area consistently greener.

In the past, we have experimented with filling the swales with mulch, (straw, hay, manure, green manure etc.) however, as this increased the number of snakes we found in the vicinity we stopped this practice several years ago, and they remain as shallow (25cm), and 60cm wide trenches with small (30cm) banks on the south side.

This year, we added a trial swale to our one acre experimental grazing land adjoining the garden. We hope this hope this will slow run-off and allow more water to be absorbed into the ground for grass growth.

Permaculture rainwater harvesting principles really aren’t all that new…
For us, possibly the most interesting observations are that we are far from the first to make these types of permaculture inspired rain water harvesting structures on this land. Our small valley, is today, undisturbed by modern intensive agriculture, and boasts not only numerous keyline dam structures throughout its lowest points, but there is also clear evidence of swales positioned on the downward slopes.

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