Dam building at Timaru Creek outfall

But you find yourself looking twice. Has the barrier formed by chance like that? You look again, no of course not. Kid dam builders have been at work. This small dam seemed to me a good example of Boltzman’s “elegant redefinition of entropy as a measure of the probability of a molecular distribution” (Lovelock, p31) or a stones-on-the-beach distribution. Compare it to the scene just 10 metres further downstream…

10 metres downstream

… entropy is increasing, but it is not without some patterns that suggest the dry course of a stream. Occasionally, after heavy rain, and in stormy weather, the outgoing stormwater battles the salt sea waves for supremacy. Where the shingle will be next day is anybody’s guess.

Energy source feature set

Some people want to put a tick under sustainable for nuclear. Note that Lovelock does not promote nuclear as the solution for all time, only until sustainable, green, renewable technologies catch up to where they can cope (e.g. conducting polymers enable the wide adoption of cheap PV). Some people want to put a tick under sustainable for hydropower, but many of the big dams have a finite lifespan because of siltation. Geothermal has not been considered here, I thought I might want to group it with solar.

The points Divan and Kreikebaum are making in their article is that there isn’t enough land and water for biofuels to be sustainable; that solar is the only one with a tick under sustainable. They have a model we can play with.

Exploring with Poppy

Most afternoons Poppy and myself go out and explore the edges, the interfaces, the ecotones and the interstices (Holmgren, p223). Poodles are intelligent dogs, second only to Border Collies, and her enhanced senses draw my attention to details I would otherwise miss. She isn’t (I imagine) heavily hung up on classification, or reducing whole systems to a list of components, or explaining the ecotones with Venn diagrams. Rather, her attention seems to go to the most interesting thing she finds at any given moment. It’s exploratory, and recreational, and fun.

Vertical waterwheels evolved from the water lever, the noria and the horizontal watermill about 200 B.C. (Reynolds). They came in three flavours: undershot, overshot and breast. The shape of the buckets was improved on over time, otherwise the waterwheel of 2000 years ago is much the same as the waterwheel of today.

The obvious difference — from the outside — is that this waterwheel (unlike the turbine of a conventional micro hydro scheme) works in the run of the river with near zero head. “We want to generate energy from water between 20cm and two metres deep. No one else has attempted anything like this in such shallow water,” Gilmartin is reported to have said in his local paper The Westmorland Gazette.

The less obvious difference — on the inside — is the real innovation. Instead of the wheel being round, the wheel is more of a belt.

If you want to read more about it there is a good article with drawings on Rexresearch.

The Chatham Islands are in an invidious position when one considers peak oil, continuing instability in the oil-producing regions, and rising barrel prices. Burning around 1500 litres of diesel a day to generate electricity is pushing prices as high as .75 cents a unit with attendant social consequences. It also leaves the islanders totally exposed to the risk that fuel prices could rise at any time. The previous government encouraged the Chatham Islands Enterprise Trust (CIET) and Chatham Islands Electricity Co (CIEL) to pursue a feasibility study for a $20m hydro scheme on the Te Awainanga river that would have gone a long way to meeting the island’s demand. Now that scheme has been dropped, leaving the Trust and the Electricity Co to wear the unrecoverable costs of the feasibility study. While wind is now the preferred flavour of renewable, and two turbines are ordered, my focus here is on the hydro opportunities which are not entirely shelved.

Te Awainanga lower waterfall

The plan now is to build a 2-meter dam at the lowest of the three Te Awainanga waterfalls, and install a 55kW turbine. By achieving this with (comparatively) low levels of funding it is hoped to build confidence and attract funding to go up to the next waterfall, and one day to the third and highest of the three (not pictured here).

Ian at Te Awainanga middle falls

Small is beautiful, one has to say, and the environmental impact is likely to be less than the abandoned big scheme. A fourth waterfall on the Mungahou (pictured below) also has hydro potential.

Mangahou falls

When I spoke to Terry Tuanui (Chairman, Chatham Islands Electricity) about the destruction of what I saw as valuable tourism assets (these incrediby lovely waterfalls) it cut little ice. “We have more urgent problems to solve here before we start worrying about tourism,” Terry said (or words to that effect).  The waterfall at Mungahou is one of the most beautiful places I have ever had the opportunity to visit, but it’s worth 100kW for 9 months of the year to the islanders. Sadly, but understandably, there is little sentiment lost over a bit of eye candy.

UK 400L/sec 3m head 3 years old.

Asking price £6000 (GBP). Will pallet freight to mainland UK addresses or export if buyer arranges transport. Can send photos for genuinely interested enquiries.

Craig listed this item on the microhydro Yahoo group to which I subscribe. It is listed here by agreement with him. If you’re interested email Craig direct craig@claptonmill.co.uk

Participant Observation, A Guide for Fieldworkers by Dewalt and Dewalt, published by AltaMira.

Dewalt & Dewalt, Participant Observation

Engineering is only one part of a hydro power project, by far the larger and harder part is socio-economic. Local politics come into it, and play a large part in the success or subsequent failure of a project.

I was looking for a book that would turn me into an instant anthropologist, one that would give me some practical tools for use in ethnographic field work.

Kathleen and Billie Dewalt’s text has proved to be just the thing. Nicely sprinkled with anecdotes from their own fieldwork in Mexico they cover topics like “Becoming a participant”, and “Becoming an observer”. The authors teach you how to write, manage and code field notes. They discuss ethical issues. Finally they give the reader some examples from real field notes.

This book is an easy read. If you haven’t been trained in ethnographic research it will leave you equipped to make a tentative start. If you want the full monty then you need Bernard’s Research Methods in Anthropology otherwise you’re set to go with Dewalt.

Micro-hydro Design Manual by Adam Harvey (with Andy Brown, Priyantha Hettiarachi and Allen Inversin) published by Intermediate Technology Publications Ltd

Harvey, Micro-hydro Design Manual

This book is a procedural manual for how to build a run-of-the-river micro-hydro scheme for a village community in a developing nation. It is the combined wisdom of a team of engineers who gained field experience in Peru, Nepal, and Sri Lanka. If you were a team of practical engineers, even if you had never built any hydro scheme before, I believe you could after reading this book. The authors cover every aspect from pre-feasibility through hydrology and geology to design and construction, to maintenance and management. Various configurations are diagrammed. No stone is left unturned in this A4 format, 374-page book. It is in the range 200 watts to 300kW, but you could scale much of the knowledge. I have come to call it simply ‘Harvey’, as you do with texts to which you constantly refer.

Here is a summary of contents to help you decide whether this is the book for you:

• Hydrology and site survey
• Civil works
• Commercial engineering
• Turbines
• Governing
• Drive systems
• Electrical power
• Financial evaluation
• Operation and maintenance
• Commissioning and testing

I notice that quite a few people planning home micro-hydro schemes consider buying this book. I would suggest it’s worth purchasing it. Much of the material would scale down to “pico-hydro”. Many of the surveys (like the Capability and demand study) are questions you should probably be asking yourself before you start.