And to think…

Many of you must have watched the news headlines on TV this week; many might have gathered it from the ‘net.

Mumbai—and much of Maharashtra—has gone down under. Under water.

And to think that all this water is now going to go purely to waste, completely unused.

… And that, starting some time right from say February next year, we are once again going to yell desperately about water shortage, about how water-tankers have already begun plying on the “roads” near the drought-hit villages. … May be we will get generous and send not just 4-wheeler tankers but also an entire train to a drought-hit city or two…

Depressing!


OK. Here’s something less depressing. [H/t Jennifer Ouellette (@JenLucPiquant) ]:

“More than 2,000 years ago, people were able to create ice in the desert even with temperatures above freezing!” [^]

The write-up mentions a TED video by Prof. Aaswath Raman. Watched it out of idle interest, checked out his Web site, and found another TED video by him, here [^]. Raman cites statistics that blew me!

They spend “only” $24 billion on supermarket refrigeration (and other food-related cooling), but they already spend $42 billion on data-center cooling!!


But, any way, I did some further “research” and landed at a few links, like the Wiki on Yakhchal [^], on wind-catcher [^], etc.  Prof. Raman’s explanation in terms of the radiative cooling was straight-forwards, but I am not sure I understand the mechanism behind the use of a qanat [^] in Yakhchal/windcatcher cooling. It would be cool to do some CFD simulations though.


Finally, since I am once again out of a job (and out of all my saved money and in fact also into credit-card loans due to some health issue cropping up once again), I was just idly wondering about all this renewable energy business, when something struck me.


The one big downside of windmills is that the electricity they generate fluctuates too much. You can’t rely on it; the availability is neither 24X7 nor uniform. Studies in fact also show that in accommodating the more or less “random” output of windmills into the conventional grid, the price of electricity actually goes up—even if the cost of generation alone at the windmill tower may be lower. Further, battery technology has not improved to such a point that you could store the randomly generated electricity economically.

So, I thought, why not use that randomly fluctuating windmill electricity in just producing the hydrogen gas?

No, I didn’t let out a Eureka. Instead, I let out a Google search. After all, the hydrogen gas could be used in fuel-cells, right? Would the cost of packaging and transportation of hydrogen gas be too much? … A little searching later, I landed at this link: [^]. Ummm… No, no, no…. Why shoot it into the natural gas grid? Why not compress it into cylinders and transport by trains? How does the cost economics work out in that case? Any idea?


Addendum on the same day, but after about a couple of hours:

Yes, I did run into this link: “Hydrogen: Hope or Hype?” [^] (with all the links therein, and then, also this: [^]).

But before running into those links, even as my googling on “hydrogen fuel energy density” still was in progress, I thought of this idea…

Why at all transport the hydrogen fuel from the windmill farm site to elsewhere? Why not simply install a fuel cell electricity generator right at the windmill farm? That is to say, why not use the hydrogen fuel generated via electrolysis as a flywheel of sorts? Get the idea? You introduce a couple of steps in between the windmill’s electricity and the conventional grid. But you also take out the fluctuations, the bad score on the 24X7 availability. And, you don’t have to worry about the transportation costs either.

What do you think?


Addendum on 12th July 2018, 13:27 hrs IST

Further, I also browsed a few links that explore another,  solution: using compressed air: a press report [^], and a technical paper [^]. (PDF of the paper is available, but the paper would be accessible only to mechanical engineers though. Later Update: As to the press report, well, the company it talks about has already merged with another company, and has abandoned the above-ground storage of compressed air [^])

I think that such a design reduces the number of steps of energy conversions. However, that does not necessarily mean that the solution involving hydrogen fuel generation and utilization (both right at the wind-farm) isn’t going to be economical.

Economics determines (or at least must determine) the choice. Enough on this topic for now. Wish I had a student working with me; I could have then written a paper after studying the solution I have proposed above. (The idea is worth a patent too. Too bad I don’t have the money to file one. Depressing, once again!!)


OK. Enough for the time being. I may later on add the songs section if I feel like it. And, iterative modifications will always be done, but will be mostly limited to small editorial changes. Bye for now.

 

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Micro-level water-resources engineering—8: Measure that water evaporation! Right now!!

It’s past the middle of May—the hottest time of the year in India.

The day-time is still lengthening. And it will continue doing so well up to the summer solstice in the late June, though once monsoon arrives some time in the first half of June, the solar flux in this part of the world would get reduced due to the cloud cover, and so, any further lengthening of the day would not matter.

In the place where I these days live, the day-time temperature easily goes up to 42–44 deg. C. This high a temperature is, that way, not at all unusual for most parts of Maharashtra; sometimes Pune, which is supposed to be a city of a pretty temperate climate (mainly because of the nearby Sahyaadris), also registers the max. temperatures in the early 40s. But what makes the region where I currently live worse than Pune are these two factors: (i) the minimum temperature too stays as high as 30–32 deg. C here whereas in Pune it could easily be falling to 27–26 deg. C even during May, and (ii) the fall of the temperatures at night-time proceeds very gradually here. On a hot day, it can easily be as high as 38 deg C. even after the sunset, and even 36–37 deg. C right by the time it’s the mid-night; the drop below 35 deg. C occurs only for the 3–4 hours in the early morning, between 4 to 7 AM. In comparison, Pune is way cooler. The max. temperatures Pune registers may be similar, but the evening- and the night-time temperatures fall down much more rapidly there.

There is a lesson for the media here. Media obsesses over the max. temperature (and its record, etc.). That’s because the journos mostly are BAs. (LOL!) But anyone who has studied physics and calculus knows that it’s the integral of temperature with respect to time that really matters, because it is this quantity which scales with the total thermal energy transferred to a body. So, the usual experience common people report is correct. Despite similar max. temperatures, this place is hotter, much hotter than Pune.


And, speaking of my own personal constitution, I can handle a cold weather way better than I can handle—if at all I can handle—a hot weather. [Yes, in short, I’ve been in a bad shape for the past month or more. Lethargic. Lackadaisical. Enervated. You get the idea.]


But why is it that the temperature does not matter as much as the thermal energy does?

Consider a body, say a cube of metal. Think of some hypothetical apparatus that keeps this body at the same cool temperature at all times, say, at 20 deg. C.  Here, choose the target temperature to be lower than the minimum temperature in the day. Assume that the atmospheric temperature at two different places varies between the same limits, say, 42 to 30 deg. C. Since the target temperature is lower than the minimum ambient temperature, you would have to take heat out of the cube at all times.

The question is, at which of the two places the apparatus has to work harder. To answer that question, you have to calculate the total thermal energy that has be drained out of the cube over a single day. To answer this second question, you would need the data of not just the lower and upper limits of the temperature but also how it varies with time between two limits.


The humidity too is lower here as compared to in Pune (and, of course, in Mumbai). So, it feels comparatively much more drier. It only adds to the real feel of a real hot weather.

One does not realize it, but the existence of a prolonged high temperature makes the atmosphere here imperceptibly slowly but also absolutely insurmountably, dehydrating.

Unlike in Mumbai, one does not notice much perspiration here, and that’s because the air is so dry that any perspiration that does occur also dries up very fast. Shirts getting drenched by perspiration is not a very common sight here. Overall, desiccating would be the right word to describe this kind of an air.

So, yes, it’s bad, but you can always take precautions. Make sure to drink a couple of glasses of cool water (better still, fresh lemonade) before you step out—whether you are thirsty or not. And take an onion with you when you go out; if you begin to feel too much of heat, you can always crush the onion with hand and apply the juice onto the top of your head. [Addendum: A colleague just informed me that it’s even better to actually cut the onion and keep its cut portion touching to your body, say inside your shirt. He has spent summers in eastern Maharashtra, where temperatures can reach 47 deg. C. … Oh well!]

Also, eat a lot more onions than you normally do.

And, once you return home, make sure not to drink water immediately. Wait for 5–10 minutes. Otherwise, the body goes into a shock, and the ensuing transient spikes in your biological metabolism can, at times, even trigger the sun-stroke—which can even be fatal. A simple precaution helps avoid it.

For the same reason, take care to sit down in the shade of a tree for a few minutes before you eat that slice of water-melon. Water-melon is nothing but more than 95% water, thrown with a little sugar, some fiber, and a good measure of minerals. All in all, good for your body because even if the perspiration is imperceptible in the hot and dry regions, it is still occurring, and with it, the body is being drained of the necessary electrolytes and minerals. … Lemonades and water-melons supply the electrolytes and the minerals. People do take care not to drink lemonade in the Sun, but they don’t always take the same precaution for water-melon. Yet, precisely because a water-melon has so much water, you should take care not to expose your body to a shock. [And, oh, BTW, just in case you didn’t know already, the doctor-recommended alternative to Electral powder is: your humble lemonade! Works exactly equivalently!!]


Also, the very low levels of humidity also imply that in places like this, the desert-cooler is effective, very effective. The city shops are full of them. Some of these air-coolers sport a very bare-bones design. Nothing fancy like the Symphony Diet cooler (which I did buy last year in Pune!). The air-coolers locally made here can be as simple as just an open tray at the bottom to hold the water, a cube made of a coarse wire-mesh which is padded with the khus/wood sheathings curtain, and a robust fan operating [[very] noisily]. But it works wonderfully. And these local-made air-coolers also are very inexpensive. You can get one for just Rs. 2,500 or 3,000. I mean the ones which have a capacity to keep at least 3–4 people cool.(Branded coolers like the one I bought in Pune—and it does work even in Pune—often go above Rs. 10,000. [I bought that cooler last year because I didn’t have a job, thanks to the Mechanical Engineering Professors in the Savitribai Phule Pune University.])


That way, I also try to think of the better things this kind of an air brings. How the table salt stays so smoothly flowing, how the instant coffee powder or Bournvita never turns into a glue, how an opened packet of potato chips stays so crisp for days, how washed clothes dry up in no time…

Which, incidentally, brings me to the topic of this post.


The middle—or the second half—of May also is the most ideal time to conduct evaporation experiments.

If you are looking for a summer project, here is one: to determine the evaporation rate in your locality.

Take a couple of transparent plastic jars of uniform cross section. The evaporation rate is not very highly sensitive to the cross-sectional area, but it does help to take a vessel or a jar of sizeable diameter.

Affix a mm scale on the outside of each jar, say using cello-tape. Fill the plastic jars to some level almost to the full.

Keep one jar out in the open (exposed to the Sun), and another one, inside your home, in the shade. For the jar kept outside, make sure that birds don’t come and drink the water, thereby messing up with your measurements. For this purpose, you may surround the jar with an enclosure having a coarse mesh. The mesh must be coarse; else it will reduce the solar flux. The “reduction in the solar flux” is just a fancy [mechanical [thermal] engineering] term for saying that the mesh, if too fine, might cast too significant a shadow.

Take measurements of the heights of the water daily at a fixed time of the day, say at 6:00 PM. Conduct the experiment for a week or 10 days.

Then, plot a graph of the daily water level vs. the time elapsed, for each jar.

Realize, the rate of evaporation is measured in terms of the fall in the height, and not in terms of the volume of water lost. That’s because once the exposed area is bigger than some limit, the evaporation rate (the loss in height) is more or less independent of the cross-sectional area.

Now figure out:

Does the evaporation rate stay the same every day? If there is any significant departure from a straight-line graph, how do you explain it? Was there a measurement error? Was there an unusually strong wind on a certain day? a cloud cover?

Repeat the experiment next winter (around the new year), and determine the rate of evaporation at that time.

Later on, also make some calculations. If you are building a check-dam or a farm-pond, how much would be the evaporation loss over the five months from January to May-end? Is the height of your water storage system enough to make it practically useful? economically viable?


A Song I Like:

(Hindi) “mausam aayegaa, jaayegaa, pyaar sadaa muskuraayegaa…”
Music: Manas Mukherjee
Singers: Manna Dey and Asha Bhosale
Lyrics: Vithalbhai Patel

Micro-level water-resources engineering—7: Dealing with the [upcoming] summer

Last monsoon, we’ve mostly had excess rain-fall in most parts of Maharashtra, even over India, taken as a whole.

Though the weather in Maharashtra still is, for the most part, pleasantly cool, the autumn season this year (in India) is about to get over, right this month.

Therefore, right now, i.e. right at the beginning of February, is the perfect time to empirically check the water levels in all those check-dams/farm-ponds you have. … That’s because, evaporation is going to happen at an accelerating pace from now on…

Between end-October (say Diwali) and March (say Holi), every solar year in India, the reduction in the levels of the stored water is dominated by the following two factors:
(i) seepage (i.e. the part which occurs after the rains cease), and
(ii) usage (i.e. the irrigation for the “rabbi” (i.e. the winter agricultural) season).

But from now on, the dominant factor is going to be the third one, namely, (iii) evaporation, and it is going to be increasingly ever more important throughout the upcoming summer, i.e., until the arrival of the next monsoon.

As I had earlier pointed out in this series  [^][^], in Maharashtra, the losses due to evaporation are expected to be about 5–8 feet (or 1 to 1.5 “puruSh”) deep.

Don’t take my word for it. … Go out and actually check it out. (Take snap-shots for your own record, if you wish.)

The beginning of February is also the perfect time to start executing on your plans for any maintenance- or new construction-activities on any check-dams/farm-ponds/residential water conservation that you might have thought of, in your mind. If you start executing on it now, you still have a very realistic framework of about 4–4.5 months left, before the next monsoon rains are slated to arrive [give or take about a half month here or there].

…Just a reminder, that’s all.


Keep in touch, best, and bye for now…


[As usual, I may come back and edit this post a bit after its publication, say, after a couple of days or so… I don’t know why, but things like that—viz., thinking about what I did happen to write, always happen to me. But the editing wouldn’t be too much. … OK. … Bye [really] for now.]

 

Micro-level water-resources engineering—6: Evaporation

As compared to the last year, public awareness about water resources has certainly increased this year. It has been a second drought-year straight in a row. None can miss it—the water issue—now. [Not even the breweries.]

There are several NGO initiatives involved in the awareness campaigns, as always. Even celebrities, now. Also politicians.

The heartening part this year is that there also is now a much greater participation of the common people.

Indeed, water conservation schemes are these days receiving quite a broad-based support, cutting across all political party-lines. People are actively getting into the building nallah-bunds, farm-ponds, and all. Good.

Good? … This is India, so how can anything be so straight-forwardly good?

With that question mark, I began taking a second look at this entire scene. It all occurred to me during a show that I saw on TV last week or so.

Well, that way, I don’t watch TV much. At least in India, TV has gone beyond being a stupor- or passivity-inducing device; it has become an active noise generator. So, the most I can put up with is only some channel-flipping, once in a while. [In my case it is typically limited to less than 15 minutes at a time, less than 7 times a week]. In one such episode [of flipping through the channels], I happened to catch a few minutes of a chat that some Marathi journos were having with Aamir Khan and Satyajit Bhatkal. [They should have been in awe of Bhatkal, but instead were, of Aamir Khan. [Journos.]]

Both Khan and Bhatkal were being all earnest and also trying to be all reasonable on that show, and in that vein, at one point, Bhatkal mentioned that there have been hundreds (or thousands) of KT-weirs, nallah-bunds and all, which have been implemented by the successive Maharashtra State governments. These are the structures or works which now have become defunct because of a lack of maintenance. Mentioning this point, he then added something like the following: [not his precise words, but as my casual impression of what he effectively was saying]:

For the best or the most optimum utilization of the available money, it would be better to begin with a revival or maintenance (like silt-removal/wall-repairs) of these thousands of the already existing structures, rather than building everything anew, because the latter would cost even more money.

Looks like quite sensible an approach to take, doesn’t it?

Well, yes, on the face of it. But not so, once you begin to think like an engineer about it. In fact, I do want to raise one flag here—one very big, red flag. [No, I am not a communist, just in case you have begun reading this blog only now.]

Let’s look at some hard facts—and also some simplest physical principles—first.


The only primary source of water is: the rainfall.

The two means of conserving water are: (i) surface storage, and (ii) ground-water recharge.

The two big [physical] enemies of water conservation are: (i) run-off and (ii) evaporation.

Run-off means: Rain-water running off the earth’s surface as floods (may be as flash-floods), without getting intercepted or stored anywhere. Evaporation means: the loss of the stored water due to ambient heat.

It’s good that people have gotten aware about the first part—the runoff factor. The by-now popular Marathi slogan: “paaNee aDavaa, paaNee jirawaa” [English: “block water, percolate water”] refers to this first factor. Unfortunately, it has come to refer to only the first factor.

People must also become fully aware about the second factor—namely, evaporation. It too is just as important in India, particularly in places like Maharashtra.

Evaporation is not always an acute concern in the cooler climates (think USA, Canada, Europe, Japan, Australia, New Zealand). But it is, in the hotter climates (think most of the third world). My focus is exclusively on India, mostly on Maharashtra. Since most of the advanced countries happen to lie in the cooler regions, and since in India we habitually borrow our engineering common-sense from the advanced countries rather than developing it individually here, I want to once again stress this point in this series.


As I mentioned in my last post in this series [^]:

“Evaporation is a really bad factor in hot climates like India. At the level of large-scale dams and even for check dams, there is precious little that can be done about it.”

There is a technological reason behind it: You can’t sprinkle some powder or so to cover the surface of a water body, and thereby arrest or slow down the evaporation losses, without also polluting water body in the process.

These days, you often see a layer of water hyacinth in dams/rivers. Thought the plant contiguously covers the water body, contrary to the naive expectation, it in fact accelerates evaporation. The plant sucks water from below and perspires it out via leaves. This rate of perspiration happens to be higher than that of the plain evaporation. Further, water hyacinth has big leaves. The total surface area of the leaves is many times greater than the area of the water body that the plant covers.

But, yes, the simple-minded idea is right, in a way. If instead of the water-sucking water-hyacinth, something else—something chemically inert and opaque—were to cover the water body, then it would cut down on the evaporation losses. People have tried finding such a material, but without success. Any suggested solutions are either not scalable, not economical, or both. That’s why, evaporation is a fact that we must simply learn to live with.


Let me continue quoting from my aforementioned post:

“Evaporation maps for Maharashtra show losses as high as 1.5 m to even 2.5 m per year. Thus, if you build a check-dam with a 3 m high wall, expect to lose more than half of the [stored] water to evaporation alone.

For the same reason of evaporation, most nallah-bunding and contour-trenching works [such as] those typically undertaken under the socialist programs like MNREGA don’t translate to anything at all for storage, or for that matter, even for seepage. Typically, the bunds are less than 1 m tall, and theoretically, water in them is expected to plain evaporate out right before December. Practically, that anyway is the observation! […] It is a waste of money and effort.”

That’s what I had said, about a year ago. It needs to be repeated.

Most people currently enthusiastic about water conservation simply don’t seem to have any appreciation as to how huge (and how hugely relevant) this factor of evaporation is. Hence this post.


To repeat: In Maharashtra, the range of evaporation losses is as high as 1.5–2.5 m. That is, about 5–8 feet, in terms of the height of water lost.

Thus, if you build or repair a nullah-bund that is about 10 feet tall (which is the typical height of a house), then you should expect to lose about 75% of the stored water to evaporation alone. Perhaps even 90% or more. After all, nullahs and rivers typically have a progressively smaller width as we go deeper, and so, the volume of the water body remaining at the bottom after evaporation is even smaller than what a simple height-based calculation tells you.

Coming back to the Khans and Bhatkals, and Patekars and Anaspures: If the small check-dam or Kolhapur-type of bund/weir you are repairing this summer is, say, 7–8 feet high, then what you should expect to see in the next March or April is: a dry river-bed with a few puddles of water perhaps still lingering here and there. Picture a stray dog trying to satisfy his thirst from a puddle that is relatively cleaner from among them, but with a vast patch of a darkish brown, rocky or parched land filling the rest of your visual field. In no case should you picture a large body of clean water extending a couple of kilometers or more upstream of the bund. The fallen rain-water would have got blocked by that bund, sure, but if your bund is only 7–8 feet tall, then all of it would have disappeared [literally] in the thin air through evaporation alone, by the time the summer arrives. [We are not even counting seepage here. And realize, not all seepage goes towards meaningful groundwater recharge. More on it, may be, later.]

Now, the fact of the matter is, many, many KT weirs and bunds, as built in Maharashtra, are hardly even 5–6 feet tall. (Some are as low as just 3–4 feet tall.) They are, thus, not even one (Marathi/Sanskrit word) “puruSh” deep. …

The next time you go for an outing, keep an eye for the bunds. For instance, if you are in Pune, take an excursion in the nearby Purandar taluka, and check out the series of the bunds built by the PWD/Irrigation department on the Neera river. Most of them are just 3–5 feet tall. None is as big as a “puruSh” tall. None ever shows any water left after December. [But don’t therefore go and talk to the PWD/Irrigation engineers about it. These engineers are smart. They will tell you that those are flood-control structures, not water-storage structures. You will thus come back non-plussed. You are warned.]

… In case you didn’t know what “puruSh” means: Well, it’s a traditionally used unit of depth/height in India. It is defined as the uppermost reach of a man when he stands upright and stretches his arms up. Thus, one “puruSh” is about 7–8 feet. Typically, in earlier times, the unit would be used for measuring the depth of a well. [During my childhood, I would often hear people using it. People in the rural areas still continue using it.]

So keep the following capsule in mind.

In most parts of Maharashtra, expect the evaporation losses to be about one “puruSh” deep.

If the water-body at a nallah-bund/check-dam/farm-pond is one “puruSh” deep during the monsoon, then expect its water body to completely dry up by the time the summer arrives the next year.

Therefore, an urgent word of advice:

If you are building farm-ponds or undertaking repairs of any bunds or KT weirs structures this year, then drop from your planning all those sites whose walls are not at least 2.0 “puruSh” tall. [If a wall is 2.0 purush tall, the water body will be about 1.5 purush deep.] Evaporation losses will make sure that your social-work/activity would be a complete waste of money. The successive governments—not just politicians but also social workers, planners, bureaucrats and engineers—have already wasted money on them. Let the wastage stop at least now. Focus from now on only on the viable sites—the sites where the depth of the water-body would be at least 12–15 feet or so.

If the nullah is not naturally deep, and if the local soil type is right, then you may think of deepening it (to a sufficient minimum depth), perhaps with machinery and all.

But in any case, keep the factor of evaporation in mind.


As pointed out in my earlier posts in this series, given the geological type of the top layers in most parts of Maharashtra, seepage is not a favorable option for water conservation planning.

The only exception is the patch that runs across Dhule, Jalgaon through Wardha, Nagpur. There, the top-layer is sufficiently sandy (as in Rajasthan.) Mr. Suresh Khanapurkar has done a lot of seepage-related work in this patch, and groundwater recharge indeed is a viable option there.

But remember: seepage is not viable for most of the remaining parts of Maharashtra (and in fact, it also is not, over very large patches of India). So, if your idea is to build shallower bunds with the expectation that it would help improve groundwater levels via seepage during and soon after monsoon (i.e., before evaporation kicks in the months following the monsoon), then that idea is not so much on the target, as far as Maharashtra is concerned. Engineering for seepage can be viable only if the local geology favors it.

For the general-purpose water conservation, in most parts of Maharashtra, we have to look for storage, not seepage. Therefore, evaporation becomes a more important factor. So, avoid all shallower sites.

In particular, when it comes to farm-ponds, don’t build the shallower ones even if government gives you subsidy for building them (including for the blue plastic sheet which they use in the farm-ponds to prevent the wasteful seepage). If your pond is shallow, it would once again be a waste of money, pure and simple. Evaporation would make sure of that.

That’s all for now, folks.


Yes, I have been repetitive. I don’t mind. I want to be repetitive, until the time that social workers and engineers begin to show a better understanding of the engineering issues involved in water conservation, esp. the factor of evaporation. Currently, an appreciation of this factor seems to be non-existent.


My blogging in the upcoming weeks will be sparser, because I have to re-write my CFD course notes and research related notes, simulation programs, etc. I lost them all during my last HDD crash. I want to complete that part first. So excuse me even if I don’t come back for some 3–4 weeks or more for now. I will try to post a brief note or two even if not a blog post, but no promises. [And, yes, I have now begun my weekly backups, and am strictly following the policy—the notifications from the operating system.]

Bye for now.


[May be one more editing pass, later today or tomorrow… Done.]

[E&OE]

Summer, boredom, city skyline, etc.

Boredom. That’s what my life has become of late. … Boredom. … Pure boredom.

Life is boring.

Nothing interests me. Don’t feel like writing anything.

No, it’s not called a writer’s block. To have a writer’s block, first you need to be a writer. And my problem is that I don’t even want to be a writer. Not even just a plain reader. Both are boring propositions.

Life, somehow, has become boring to that great an extent.

Summers always do that to me.


While at IIT Madras, we (a few friends of mine and I) had begun using a special term for that: (Sanskrit) “glaani.”

Usage pattern:

“Did you work out those lab calculations?”

“.” [No answer from me.]

“Ajit, did you complete those lab calculations?”

“.” [No answer.]

“Machchaa…”

“.” [Still no answer.]

The fellow turns around, lethargically. [He, too, doesn’t have much energy left to pursue anything; the heat has been that bad…] … Begins to drag his feet back to his room.

“glaani.” [One attempts some answer, some explanation.]

The fellow does not even care to look back.

The use-case scenario is over.

Currently, it’s summer time, and this year in particular, I am finding it even more lethargy-inducing and boring than it usually is…


Here is an idea I had. I wanted to expand it in a blog post. But since everything has become so summer-ly boring, I am not going to do that. Instead, I will just mention the idea, and let it go at that.

How do you visually estimate the water requirements of a human settlement, say, a city? Say a city with skyscrapers, like Mumbai? (Skyscrapers? In Mumbai? OK, let’s agree to call them that.)

Start with a decent estimate of per capita water requirement. Something like, say, 135 liters/day/person. That is, 1.35 \times 10^2 \times 10^{-3} = 1.35 \times 10^{-1} cubic meters. For one year, it translates to 0.135 \times 365 = 49.275 \approx 50 cubic meters.

An average room in an average apartment is about 10 feet X 12 feet. With a standard height of 10 feet, its volume, in cubic meters, is: 3.048 \times 3.6576 \times 3.048 = 33.98 \approx 35 cubic meters.

Of course, 135 liters/day is an estimate on a slightly higher side; if what I recall is right, the planning estimates range from even as low as 50 liters/day/person. So, taking a somewhat lower estimate for the daily per capita requirement (figure out exactly how much), you basically arrive at this neat nugget:

Think of one apartment room, full of water. That much volume each person needs, for the entire year.

If one person lives in one room (or if a family of four people lives in a 2BHK apartment), then the volume of that apartment is their yearly water requirement.

Hardly surprising. In the traditional water-harvesting in Rajasthan, they would have single-storied houses, and roughly the same volume for an underground reservoir of water. Last year, I blogged quite a bit about water resources and water conservation; check out tags like “water resources” [^].

So, the next time you look at a city skyline, mentally invert it: imagine a dam-valley that is just as deep as the skyline’s height, containing water for that skyline. That would be the residential water requirement of that city.

Of course, if the population density is greater, if one apartment room accommodates 2, 3 (or even more number of) people (as is the common in Mumbai), then the visualization fails. I mean to say: You then have to imagine a deeper (or wider) dam valley.

… I used to be skeptical of residential water harvesting schemes. I used to think that it was a typical NGO type of day-dreaming, not backed up by hard data. I used to think that even if every 3-story apartment building covered its entire plot area (and not just the built-up area) with a 1 to 2 story-deep tank beneath it, it wouldn’t last for even a couple of months. But when I did the actual calculations (as above), I became convinced of the utility of the residential water harvesting schemes—if the storage is big enough.


Of course, as one often hears these days, if common people are going to look after everything from electricity (portable gen-sets, batteries and inverters), water (residential water harvesting), garbage (composting in the house/terrace garden), even security (gated communities with privately paid watchmen), then what the hell is the government for?

If your anger has subsided, realize that only the last (security) falls under the proper functions of government; the rest should actually be services rendered by private businesses. And if government gets out of every thing but the defense, the police and the courts, the economic progress would so humongous that none would bother reading or writing blog posts on residential water conservation schemes—there would be very competent businesses with private dams and private canals to deliver you clean water very cheaply (also via private trains, if the need be)… But then, I am not going to write about it.  Writing is boring. Life is boring. …. So, just look up Ayn Rand if you want, OK?

… Yawns. Life is boring.

BTW, did you notice that boring also means digging, and I was somehow talking about inverting the skyline, i.e., imagining wells and valleys. Kindaa double meaning, the word “boring” happens to have, and I happen to have used it in both senses, haven’t I?

Oh well. But really, really speaking, I meant it only in the simplest, most basic sense.

Life is boring. … Yawns….

[E&OE]

 

 

Micro-level water-resources engineering—4

Further Update on 2015.04.13: The debugged version is online.

Here is the zip file for the debugged version [^]. I have updated the link in the main text below, too. The bug consisted of a single change: In the file CCheckDamsSeries.cpp, line 228, it should be dEX1 = dX2 - dEWaterLength; in place of dEX1 = dX2 - dWaterLength;. That’s all. (Copy-pasting codes always introduces errors of this sort.)

What I have now uploaded is only the (corrected) first version, not the entirely rewritten second version (as mentioned in the first update below). Two reasons for that: (i) The first version itself is good enough to get some overall idea of the benefits of check dams, and (ii) I have decided to try Python for the more elaborate and completely rewritten version. The reason for that, in turn, is that I just got tired of compiling the binaries on two different platforms.

That way, I am new to Python, and so, it will take a while before you get the expanded and rewritten version. I am learning it the hard way [^].  May be a couple of weeks or so for the next version… Bye for now.

Important Update on 2015.04.12: The software is buggy.

I have noticed (at least one) bug in the software I wrote (see details below). It came to my notice today, once I began completely rewriting the code with a view to study how the economics would work out at different gradients of the river (keeping all the other variables constant, that is). The bug concerns the calculation of the water volume after evaporation, in each dam.

Please give me a few days’ time, at the most a week, and I will upload a (hopefully) correct and a much better written code.

In the meanwhile, I am keeping the current buggy code at the link provided below just in case you want to debug it or play with it, in the meanwhile. Once the new code is ready, I will remove the current buggy code and replace it with the new code.

* * * * *   * * * * *   * * * * *

The last time, I had suggested an exercise to you. I had not actually undertaken that exercise myself, before writing about it on the blog.

Once I began calculating manually, I realized that the calculations were highly repetitive. I therefore decided to write a quick-and-dirty C++ program about it.

It takes a few input parameters concerning the geometrical dimensions of the highly simplified model river, generates a series of check dams, and calculates the volumes of water that would get stored.

The program also takes into consideration a thumb-rule for the evaporation losses. However, the seepage losses are not considered. That will be quite a different game.

The program also calculates the number of people whose daily personal water needs would be fully satisfied by the available water storage (after deducting the loss due to evaporation, though not by the seepage).

Finally, I also threw in a very rough-and-ready calculation for estimating the costs of building the system of check-dams, and the one-time per-capita cost (for the supported population) for the round the year availability of water (assuming that all the dams do get fully filled up during the monsoon each year).

Let me hasten to emphasize that the cost calculations here are too simplistic. Don’t rely on them; take them as just rough, preliminary and merely indicative estimates.

The cost calculations also do not include any maintenance aspects—which, IMO, is an even more serious drawback for this software. I believe that dam-maintenance must be factored in right at the stage of design—including periodic maintenance for the mechanized removal of the accumulated silt.

Further, costs for lift-irrigation or pumping of water are not included in this program.

Despite these limitations, it has turned out to be an interesting toy to play with!

I am sharing a link to a zip file (stored on Google Docs) containing the source code as well as the pre-compiled binaries for both Windows 7 and Ubuntu 14.04.01 LTS (both 64 bit), here [ (.zip, < 40 kB) ^]. Enjoy!

Things you could check out:

After altering some of the input parameters, I found that the total amount of water available (and hence the population that can be supported, and hence the per-capita expense) is highly sensitive to the depth of the river gorge at the mouth (i.e. at the extreme downstream end, where it joins a bigger river). Realize that this is a very simple model: the volume of the pyramid is directly proportional to the area of the base rectangle, and the fact of the slope restricts the possible storage volume in such a way that the depth of the river bed at the mouth then perhaps becomes the most important parameter in this model.

If you spot some other peculiarities, I would love to hear from you.

* * * * *   * * * * *   * * * * *

These days, I have been discussing these ideas with my father a bit. Not much, but I just passingly mentioned to him that I had written a blog post and that I mentioned about what he had told me about the geology of the Shirpur region.

Next day, he dug out from somewhere the proceedings of an all India seminar he had attended. Here are the details of the seminar: “Modern techniques of rain water harvesting, water conservation and artificial recharge for drinking water, afforestation, horticulture and agriculture,” jointly organized by the Rural Development Department of Government of Maharashtra and the Directorate of Ground Water Surveys and Development Agency, in Pune, on 19–21 November, 1990!

Wow! 1990! The proceedings are by now some 25 years old!

Yet, browsing through it, it first seemed to be how little things had changed. The contents of that seminar a generation ago are almost entirely relevant even today!

… Of course, there must have been some changes. What I got here was only a compilation of the abstracts and not the complete proceedings of all the full length papers. It is difficult to make out the progress (or its absence) looking only at abstracts. … I notice that a lot (even majority) of the papers are mostly of the sort: “This thing needs to be looked into” or “We have begun this study,” or “this approach seems to be promising.” Concrete, quantitative results are rare in the book. May be that’s the reason why the material looks very “modern” even today.

Other noticeable points: Only one or two papers make reference to GIS or material generated by GIS, or to the satellite imaging/remote sensing technologies. None provides any kind of a computational modelling. All the diagrams are drawn on paper—not computer generated. The book itself was printed, not produced via desktop publishing.

There was a participant from a foreign country—a lone foreign participant, I think. His affiliation was with the Cornell University, USA.

The title of this paper was “Optimization techniques to study the impact of economic and technical measures in recovering aquifers polluted by farming activities” (italics mine).

Even in the abstract, the author felt it important to highlight this part: “the importance of a government body which assumes a key regulatory role in managing the quality of the aquifers cannot be understated” (italics mine).

Immediately later, he also simply added, as if it were an unquestionable kind of a statement: “Both economic and technical measures are at the disposal of the government” (italics, once again, mine).

The author had grandly concluded his abstract thusly: “A theoretical model is developed that may assist the government in determining proper policies under various conditions of economic priorities as well as under different scenarios for relative price ratios between inputs and agricultural production” (italics emphatically are only mine).

The more things change the more…

BTW, any one for the idea that participation from Ivy League schools uplifts the quality of Indian conferences?

It’s a 140 pages book, and I haven’t finished even browsing all through it. My father gave it to me only yesterday noon, and, as you know, I have been writing this program since yesterday afternoon, and so didn’t find much time for this book.

However, I did notice one very neat abstract. So neat, that I must share it fully with you. It forms the content of the next section.

* * * * *  * * * * *   * * * * *

“Indian Rainfall and Water Conservation,” by P. R. Pisharoty, Professor Emeritus at Physical Research Laboratory, Ahmedabad.

Abstract

The average annual rainfall over the plains of India is 117 cm. The average for all the lands of the World put together is only 70 cm. per year.

In Maharashtra, 80% to 95% of the annual rainfall occurs during the monsoon period June to September. And that occurs in 85 days over the Konkan and in 35–45 days over the rest of Maharashtra. The monsoon rainfall over Konkan is 270 cm., Vidarbha 95 cm., Madhya Maharashtra 77 cm., and Marathwada 65 cm. Half of this amount (outside Konkan) falls in 15 Hours to 20 hours distributed within those 35–45 days. Being of high intensity, 3–5 cms. per hour, this half amount of total monsoon rainfall runs off the ground causing floods and much soil erosion.

This is our problem—particularly in the non-coastal Maharashtra. Only 35–45 days of any significant rain in the whole year, that too confined to the period June to September, half of the rain coming down with great intensity and running off the ground causing flood and much erosion.

We need innovative water conservation methods. We have to draw on our ancient wisdom. The characteristics of the rainfall in the European Countries and in north America are different. Their rainfall is distributed throughout the year and their intensities are not as high as those of Indian rainfall.

Construction of a very large number of water ponds, each a hectare or so in area and about 10 metres deep is one such method. It can be supplemented by check dams, underground check dams, etc. There are other water harvesting methods adopted in areas where annual rainfall is 20–30 cm. or less. Maharashtra is not that bad.

* * * * *  * * * * *   * * * * *

[In the above reproduction, I have kept the typos (15 Hours to 20 hours), the mistaken convention for writing physical units (cm. instead of cm) and the italics emphasis exactly as in the original.]

Honestly, which one of the two abstracts you liked better? Why? What kind of epistemological issues seem to be at work?

* * * * *  * * * * *   * * * * *

A Song I Like:
(Hindi) “ni sultaanaa re…”
Music: R. D. Burman
Singers: Mohamad Rafi, Lata Mangeshkar
Lyrics: Majrooh Sultanpuri

[E&OE]

 

 

 

Micro-level water-resources engineering—3

The deccan trap basalt as the most widespread feature of the geology of Maharashtra:

The geological map for India shows a large uniform portion for the deccan plateau. It consists the hard basalt rock, and not soft or sandy alluvial soils. The deccan trap basalt portion goes over Maharashtra, MP, Karnataka, and the adjacent areas from other states. (To my surprise, it seems that the geologists do not include the south Karnataka region in the same deccan trap basalt region.)

As far as regions of water-scarcity go, there is a very wide continuous band in India. Take India’s map, and mark two slanted lines: the top one going across Rajasthan, MP, Orissa, and the bottom one going across Gujarat, Maharashtra, Karnataka, Telangana and AP, even Tamil Nadu. Statistically speaking, the greatest number of the most severe droughts seem to occur in the regions falling in between these two lines.

The area of my interest is in Maharashtra. The worst drought-prone regions of Marathwada, South Maharashtra and parts of Vidarbha and Western Maharashtra all fall in between those two lines.

If Maharashtra is seen at a large, national, scale [say, 1 cm:100 km], the topmost geological layer is comprised mostly of the deccan trap basalt.

The water-seepage characteristics of the deccan trap basalt:

Speaking in general terms, if you take, say, a 10 cm X 10 cm X 10 cm cube of basalt, you will find it to be a hard, impermeable rock. You might therefore conclude that it is not very easily conducive to groundwater seepage.

However, when viewed at a larger scale, even a top-layer of basalt is not uniform either in composition or in shape (i.e. in terms of its surface morphology). First of all, there are inhomogeneities introduced and fissures formed right at the time of formation of these geological layers aeons ago. Then, there are earth-quakes, introducing cracks and fissures. Further, there also are some very slow processes that nevertheless make their effects felt over the geologically long time-scale of tens, even hundreds of thousands of years.

Due to the inhomogeneity of their composition and morphology, the daily thermal expansions and contractions experienced by the surface layers of rocks are inhomogenous. These inhomogeneities lead to thermally induced mechanical stresses. Over the geological time-scale, the repeated thermal stresses result in local fractures, especially near the surface (where the temperature gradients are the greatest). Further, the mechanical effects of erosion due to water flow leads to deposition of sand; it also serves to erode the fissure openings. The chemical action of dissolved minerals and chemicals lead to enlargement of fissures and opening of cavities at surface as well as deeper layers. Even in a nominally hard rock like basalt.

Thus, due to fracturing and weathering at the surface layers, if you consider relatively bigger patches, say those at the scale of, 10 m to a few hundreds of m (or bigger), even a top layer of a nominally hard rock like the basalt, can begin to act like the more permeable alluvial layer.

Since the cracks are highly irregular and elongated, percolation from a surface water body into the deeper underground layers is highly inhomogeneous and anisoptropic.

In the above discussion, we have considered the seepage from the surface layers. As far as the underground flow through aquifers goes, there is a presence of local sub-layering within an overall top layer of basalt. Further, fissuring and cavitation also has occurred deeper underground. Therefore, local underground aquifers are observed to exist even within an overall basalt layer. Such aquifers often are quite directional, and not too criss-cross. Hence, anisotropy (or directionality) to the local underground flow is only to be expected.

As an example of a locally restricted fracturing/fissuring, observe the groundwater falling over the passing trains and buses in the tunnels of the Khandala ghat on the Mumbai–Pune routes. (BTW, in case you have ever wondered whether these fissures/fractures pose risk, don’t worry!  Their presence is already factored in, while designing for tunnels—fracture mechanics, by now, is a fairly well understood technique.)

One notable reference here is by Prof. Deolankar of Uni. of Pune: Deolankar, S. B. (1980) “The deccan basalts of Maharashtra, India—their potential as aquifers,” Ground Water, vol. 18, no. 5, September–October 1980, pp. 434–437 [(.PDF) ^]. Note the comparisons to the basalt layers elsewhere, and the quantitative estimates for parameters such as porosity, yield, transmissivity and specific capacity.

To conclude, (i) a top layer of basalt layer also allows for seepage of water, even if (ii) the effect varies greatly from place to place (due to the inhomogeneity of fracturing) and the flow is directional (due to anisotropy).

Therefore, groundwater seepage, and therefore artificial groundwater recharge work, appears feasible even in the deccan trap region of Maharashtra. However, it is only to be expected that the seepage aspect won’t be as pronounced as in the regions having a sandy alluvial top layer.

The importance of the local geology:

Due to the local inhomogeneity and anisotropy, there also arise certain difficulties or challenges.

The main difficulty is that unless a detailed geological study of the local hydro-geology is carefully conducted, it would be impossible to tell whether any underground water recharge work would at all be feasible in a given village or not.

Artificial groundwater recharge work may lead to very impressive results in some village or a cluster of villages, but it may not at all give economical returns even in some nearby  villages—even if all of them fall under the same governmental administrative unit of a taluka (or even a block). [The same Collector; the same Block Development Officer! … Two results! (LOL!)]

Thus, in Maharashtra (and similar regions), it becomes crucially important to know what kind of local geology there is—the surface geology, as well as the geology and morphology of the underground strata.  The depth to which these features should be known would vary from place to place; it may range from 10 m to even hundreds of meters.

Unfortunately, the geological surveys in the past were conducted only at much grosser scales. The relevant geological data at the micro-level of villages (i.e. covering just 5 km X 5 km areas) are simply not available.

If experts (say GSA) are asked to conduct such surveys at the micro-level for the entire country, it would be a very time-consuming and costly process.

However, realize that what you need for the water-conservation work is not the most elaborate kinds of surveys. You don’t need surveys of the kind that GSA or the mining engineers make. You aren’t really interested in things like detailed rock-compositions, percentages of minerals, etc. Your main interest is things such as: what kind of strata run where underground, what kind of intermediate layers occur in between the layers of hard rocks and at what depths, the depth and the direction at/in which the local fissures and aquifers run, whether a given fissure extends up to surface or not, etc.

Some of this data (concerning the local geological strata) can be gathered simply by observing the traditional wells! Often-times, the wells are either not at all covered with walls, or even if there is a masonry work, it does not extend beyond a certain depth, and so, the underground layers stand adequately exposed at the traditional wells. Other data can be had by observing the exposed surfaces of nallahs, rivers, hill-sides, etc.

And, of course, data about the local underground strata can always be had by drilling observation bore-wells (though it would be a costlier method).

The economic relevance of computational modelling:

In places like Maharashtra, since the groundwater seepage, flow, and water-holding characteristics crucially involve local variations and directionality, 3D computational models should prove to be of definite use.

Use of 3D computational models would not only streamline the collection of data, it would also lead to far more accurate predictions concerning economic feasibility of projects—ahead of spending any money on them.

A case in point, here, is that of a small check-dam built at the initiative of the IIT Bombay alumni. More details can be found at the CTARA Web site. As a measure of the difficulty in making predictions for underground water flow, notice that in spite of certain geological studies (of conductivity measurements etc.) conducted by the IIT Bombay experts prior to building of this check dam, it still has not resulted in any enhanced ground-water seepage downstream. Chances are, if a 3D model were to be built by drilling observation bore-wells, either a significant amount of money could have been saved, or deployed at a more suitable location.

An apparent counter-case in point is that of the success of the Shirpur pattern, at its original location, viz., near Shirpur (where else?). No detailed micro-level 3D computational modelling was conducted for it. Still, it was successful. How come?

The local geology of the Shirpur region as not being representative of the entire state of Maharashtra:

As it so happens, my father, a retired irrigation engineer, had worked in the Shirpur area. (I thus happened to have had a considerable stint of my school education in and around Shirpur.) I had discussed the issue with my father quite a few years ago. From whatever I now recollected, he had mentioned that the local geology there indeed was more conducive to underground seepage. There were sandy soils at the top level, and some hard rock well underneath. Both these factors lead to better seepage characteristics. The strategy of deepening and widening of the nallahs, as followed in the Shirpur pattern, therefore is a good strategy. As to the rest of Maharashtra, the local geological characteristics differed, he had mentioned it.

[I guess we had this conversation some time in 2007 or 2008. I have been having this idea of not getting discouraged if there is no water at a bore-well location, but instead turn the situation on its head and use the out-coming data regarding the underlying geological strata, to build better predictive computer models at a very fine level of granularity. I have been having this idea since at least 2008, and so, our conversation must be that old. As to the appreciation of having to carefully build 3D models, I owe it to my training in materials engineering, in particular, stereology.]

Anyway, in the recent weeks, I therefore checked the local geology for the Shirpur region, consulting some of the references listed in my earlier post in this series. It turns out that the depth to the water level near Shirpur is at roughly 20–30 m bgl (i.e. below ground level); see ref. here: Aquifer Systems of India, Central Ground Water Board, Plate XXVII on page 58 [(34 MB) pdf ^]. Now, this is a region through which Taapi, a major river, flows. As any school-boy in Shirpur would know, the river has enriched the top layers with a rich black soil. What is the official geological nature of this top layer? Turns out that it is “alluvial.” The black soil does not have the best permeability. However, in the Shirpur region, the alluvial deposits also are sandy in nature, esp. as you go below a certain depth (of 1 m to a few meters). Next, check out the distinctive yellow patch of the alluvial region in this map, standing in sharp contrast to the green patch for the basalt layer for the major parts of Maharashtra [(370 kB pdf) ^].

A top layer of alluvial soil, esp. if deeper than 10 m, if it is then also supported underneath by a highly impervious layer (e.g. basalt in Maharashtra), then the approaches that seek to enhance ground-water seepage do make good sense.

In contrast, if there is a top layer of basalt itself, then, in general, it is less conducive to groundwater seepage; it is more conducive to construction of check-dams for water storage (as in contrast to water percolation/seepage), or for the Kolhapur-type weirs for both storage and redistribution, etc.

As an inevitable conclusion, the local geology holds very important implications for selection of effective water conservation strategies.

Naturally, you can’t just go ahead and apply the Shirpur pattern everywhere in Maharashtra.

“Give me the funds for a few Poclains per taalukaa, and I will make everything green,” is a statement therefore strongly reminiscent of “Give me a place to stand and with a lever I will move the whole world.” The point is not that the whole world won’t be moved; the point is the natural difficulty in providing the guy with a place to stand (complete with air to breathe etc.), not to mention the engineering difficulty of supplying him with a strong enough, and long enough, a lever. And, of course, the difficulty of arranging a place to keep the fulcrum of that lever.

Dramatic statements, both!

I will go ahead, stick my neck out, and say that the Shirpur pattern—inasmuch as it incorporates the seepage mechanism as a strategy—is not likely to be the most optimum solution at any places other than in the Tapi and the Purna river regions! Check out the map if you have not done so already [(370 kB pdf) ^]!

The idea of small dams as storage—and not seepage—devices:

Come to think of it, then, with all the due qualifications—i.e., speaking only in general terms, and only for most parts of Maharashtra (not all), and ignoring any fracturing present in the local geology—the idea of small-dams or check-dams as storage devices, rather than as a seepage devices (or as a groundwater recharge devices), has begun to make much better sense to me. …

[… Yes, the famous government-funded Poclains, and the government-funded work to be contracted out to some of the local parties, and the government funds to be timely released only to some of those parties…. The whole she-bang does stand to be applied also here; more on it, later, if at all necessary. …]

…For the time being, here is an exercise for you.

Exercise:

Take a smallish river (or a bigger nallah), say, 50 km (or 10 km) long. Build an enormously simplified geometrical model of the river, by assuming a rectangular pyramid for its water-carrying volume.

Thus, ignore all the bends in the course of the river and instead assume that the river looks like a long, acicular triangle in the plan (i.e. in the top view). Further, assume that the vertical cross-section of the river remains rectangular throughout; it goes on linearly increasing in area from zero at the origin of the river to a certain value at the end of the river.

Assume typical figures for the dimensions of the river/nallah: how about a vertical cross section that is 50 m wide and 2–3 m deep at the mid-length of the river (i.e. 25 km downstream from the origin)? Assume also a suitable slope for the river, so that water does indeed flow downstream: how about a fall in the height of the ground level of, say, 50 to 100 m, over its 50 km length?

Now, if a series of check dams were to be built on this “river” such that they would submerge some 75% of the total river area present in the plan view into water-holding areas, calculate how much total volume of water would be made available. Compare this volume to the storage capacity of a single conventional dam known to you. …

[While making your calculations, realize (i) that the max. height of the dam cannot exceed the depth of the river bed (because only the river area would go under water), (ii) that the bottom of the river slopes down, and therefore (iii) that the depth of river bed below the water surface goes on decreasing as you go upstream from the check dam location, coming to zero at some location upstream. The third factor severely delimits the total volume of water that can be held via the series of check dams.]

To put the water volume in context, assume that the per-capita consumption for daily individual consumption is some 135–150 liters. Using this assumption, determine the size of the town/city whose needs could be met by this series of check dams. (Note, this figure does not include demand for agriculture and industrial usages.)

Then, consult a practising civil engineer and find out the current cost of construction of all these check dams. Compare this cost with that of a single conventional dam.

Think about any advantages the series of check dams may have; consider water distribution, flood control, and sedimentation and maintenance aspects.

Include the costs of canal construction in the conventional approach. Include the costs of lift-irrigation schemes in the check-dams approach.

Include the fact that since check-dams won’t have a great height (say 2–4 m), the evaporation losses (estimated at about 20–30% in the conventional dams) may even lead to this circumstance: all the water in a check dam plain evaporates in the thin air even before the next summer season approaches. Realize here that, as a rule of thumb, evaporation losses over the eight non-monsoon months are as high as about 1.67 m of height loss per square m of the average of top and bottom surface areas in the plan. [To help put this figure in some kind of a context, the average annual rainfall in Maharashtra is about 110 cm—if no rainwater were to be lost to seepage, runoff or evaporation, and if all of it could be collected, a tank with a square meter of bottom surface area would hold a water body 1.1 m tall.]

Include the economics of maintenance and mechanization in the regions where there is no traditional “Rajasthan culture” of water conservation, but instead people expect government to bring them everything wherever they are.

* * * * *   * * * * *   * * * * *

I will come back later with some further notes and observations (including those on software) on this topic of micro-level water-resources engineering. In particular, I want to make a few notings related to the GIS software. However, I belong to those old-fashioned kind of engineers who, in their practical life (as in contrast to their avatars in blogosphere, for instance) always first do a quick back-of-the-envelop calculation before they switch on a computer to do any computational modelling. If you are like me, you should finish the above exercise first, so that the exploration of software is better grounded in reality.

* * * * *   * * * * *   * * * * *

A Song I Like:
(Marathi) “gangaa aali re, angaNi”
Lyrics: G. D. Madgulkar
Music: Datta Davajekar
Singers: Jayawant Kulkarni, Sharad Jambhekar, Govind Powale, H. Vasant, Aparna Mayekar

[Minor updates done right on 2015.04.08 after posting the very first version. Guess I will not make any significant revisions to this post any further. May come back and correct typos and grammatical streamlining; that’s all—no new points.]

[E&OE]

 

Micro-level water-resources engineering—2

As mentioned in my last blog post, I have been browsing material on the title subject.

In this post, let me note down a few informative links that I have (only) browsed (but not completely read through) thus far. I will come back to my own notes and observations (based on them) in the subsequent posts. BTW, I intend to keep this post as a catch-all thing: whenever I find a new interesting link, I will come back and note it here, without separately mentioning update dates and all. (I think I will also consider converting this post into a separate page of this blog or my personal Web site.)

* * * * *   * * * * *   * * * * *
Portals:

India Water Portal [^] (Web sites like these are, IMO, better than novels in English 🙂 )
Rainwater Harvesting [^]

Government and Public Sector Portals/Sites:

IMD: [^]

IITM: [^]

Central Groundwater Board:  [^]. This is a big site/portal. So, let me note down the links to some specifically relevant parts of it:  Downloads [^], Watershed [^], Aquifer Systems of India (and a few states) [^], Groundwater Yearbooks [^], Groundwater Scenario in India [^].

The World Bank funded projects in India, phase I and II: [^][^]

Books, Academics, and Professional Organizations:

A popularization kind of a book on Rajasthan’s water culture: [^]. Incidentally, it is through this book that I came to place Rajendra Singh’s work in a better context. The last time I had wondered why Singh didn’t go 400 km West. This book clarified the matter to me.

US Dept of Agriculture Report: Technical Guide to Managing Ground Water Resources [(.PDF) ^]

Groundwater Manual [^]

A book at the US GS site: [^]

A research group at CTARA, IIT Bombay: [^]. Reports and Course Materials at [^],  [^],  and [^]

A research group at IISc Bangalore: [^]. An example of a project they are carrying out: [^]

A private research cum consulting group from Pune (with many academic projects conducted with the Geology Dept. of S. P. University of Pune, too): [^]

CP Kumar’s links on hydrology [^] and on hydrology resources [^]. He works at the National Institute of Hydrology: [^]. There is a learning package for hydrology for the beginners, too: [^]

Indian Association of Hydrologists [^]

Software:

Hydrology Software:

Lists of software maintained at the USGS site, in general [^], and for groundwater in particular [^].

A proprietory software developed for use by the government agencies in India [^]:

Open-source GIS software:

Wiki list [^].

The following two seem to be more general purpose and/or leading; they also are multi-platform: QGIS (I think IIT Bombay people use it) [^], and GRASS [^].

An open-source GIS software on Windows (.NET) platform: [^]. US EPA uses it: [^]. I installed and tried it, but the documentation seems to be lagging behind the software.

ParFlow: [^]

List at the GIS Lounge: [^]

Rainfall and Its Measurement:

Annual rainfall animation [^]. Check out the animated GIF [^]. A surprise: check out the low rainfall area which the animation shows for the Konkan region. That is because while creating the animation, they coarse-grained the data. There are unexpectedly low-rainfall region even in Konkan, but these are rather isolated. Once again highlights the importance of the local data. But, it’s entertaining anyway.

Another royal entertainment (reduce your computer’s volume before hitting the link): [^]. Then, to see the actual action, hit the “Play the whole sequence” button. (This is one of the rare times that you would wish you had an Intel 386.)

Just in case you want to keep a record of the rainfall in your area, in India, we follow these specs  [(.PDF) ^].

In case you didn’t know, 1 mm of rainfall at a point means “A 0.001 m3, or 1 litre of water to each square metre of the field” [^]. … 1 cm of rainfall is ten times that number.

Exercise:

On the Internet, look up the area of a state, district, taluka, or city; look up its average annual rainfall; then find the total quantity of water (in litres) it receives via rainfall in a typical year.

Then, also do searches and find out data about its total water demand. Also, find out its current water availability, and the short-fall in the supply.

Trivia:

The average annual rainfall for India is about 70 cm in monsoon alone, and about 110 cm for the entire year (including the non-monsoon rains, snow-fall, etc.) (Source: [^]. Also see: [^]).

Floods and droughts still visit India every year.

The average annual rainfall in Jaisalmer is just 16.4 cm (less than one-fifth of that at Delhi), and all of it is received over only 10 days. (Yes, statistically speaking, as many as 355 days in a year go completely dry there.) The water-table depth there is really bad; it ranges between about 40 to 80 m (i.e., about 125 to 250 feet) [^].

Jaisalmer nevertheless has a huge lake that would supply water to the city [^] all through the year—the lake would not go dry even in summer! This lake: Image [^], video [^].

No, that lake doesn’t get its water supply from a river or groundwater sources; there is in fact no mountainous or hilly region around it. The only source of water for this lake is: an ingenious scheme for rainwater harvesting. A scheme that is almost 7 centuries old.

Now, go, figure how wasteful—and flood-hit—and water-scarce—the rest of us manage to remain even today.

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A Song I Like:
(Marathi) “ye re ghanaa ye re ghanaa…”
Music: Hridaynath Mangeshkar
Lyrics: Aarati Prabhu
Singer: Asha Bhosale

 

[E&OE]

Micro-level water-resources engineering

1. Introductory:

It’s the “Holi” day today—one of the two Indian cultural reminders that the summer is almost at the door-step. [The second reminder is the “Gudhi PaaDawaa,” the Indian lunar new year’s day, which follows after a lunar fortnight.]

The hottest—and the most water-scarce—days of late-April, May and early-June are in the coming.

This period also is the last opportunity in the year to undertake any appropriate water-conservation work.

Those who have browsed my personal Website would know that surface-flow and ground-water seepage has been a topic of some definite research interest to me. [Off-hand, I think I also have passingly mentioned about it on my blog in the past.] … That way, I haven’t actually pursued any concrete research about it; it’s just been in an exploratory stage. I do plan to do something about it once I get some right kind of students to guide along these topics, preferably ME students (from several different disciplines; see my research description at the end of this post). [BTW, even though currently I am jobless, I do anticipate to get a job in the next cycle of academic appointments that occurs sometime around the summer vacations or so.]

In the meanwhile, I have been going over some popular as well as scientific writings on the subject, thinking over the issues involved, and bringing some clarity as to what in particular I can do about it. My research would involve only computational modelling. In particular, I wouldn’t at all be interested in the sociological/governmental aspects of it, though one must be aware that they exist, and one must have at least some background kind of a sense of what they are like.

There has been a lot of coverage in the media about some of these initiatives/work. Three stand out, in the chronological order: (i) Rajendra Singh’s work in Rajasthan, (ii) Anna Hazaare’s, in Ralegan Siddhi in Maharashtra, and (iii) Suresh Khanapurkar and Amrishbhai Patel’s, in Shirpur, Maharashtra.  As usual, media’s coverage of these efforts is mostly superficial, partial/incomplete, and skewed.

Here are some of my notes after browsing about these three efforts.

1. Rajendra Singh’s work:

Rajendra Singh has by now become something of a celebrity among the NGO-type of social workers; today he even attracts the wide-eyed young (and mostly clueless) volunteers from the urban areas.

I would strongly suggest you to pursue your own browsing about Singh’s work, starting, e.g., here [^], before reading further.

Please do that first, in order to realize the extraordinary perceptiveness of this piece, written by Amanda Suutari and Gerry Marten, here [^]. I don’t know who the authors are, except for their profiles here [^]. The main article at both the links is the same.

IMO, this piece is the best among all the articles available on this topic on the Internet. Yes, this piece, too, has some pinkish shades at places. “Commercial mines” is far wider a term that seems to have deliberately been put to use here; the mines actually were relatively small, shallow, and only for the marble stone, not for other minerals. That said, still, the aforementioned pink is rather rare in that article, and it occurs mostly in some minor places that are fairly well isolated. I mean, the entirety of the article itself has not been deliberately painted with a background pinkish wash of sorts. And if you go through the article ignoring these isolated streaks of the pink, then there is a wealth of accurate observations, and minute but relevant detail. The article truly stands out from the crowd.

As far as Singh’s main work goes, from an engineer’s point of view, here are some of my unanswered questions or points:

The remote rural area of Rajasthan that Singh famously went to (and stayed in) is not in the Thar desert, but in the Aravali mountains. From the Google Earth perspective, this location is just about a stone’s throw from Jaipur—and also from the then still surviving forest park. The “before” photos, too, show some greenery on some hills—not those seemingly endless yellow and wavy sand dunes flatly spreading everywhere up to the horizon. Why must every media report emphasize “Rajasthan” as a whole, when they talk about Singh’s work? Why don’t they say the half-green Aravali parts near Delhi and MP? Two further sub-points:

  • How effective would the collection of the falling rain be, if the region weren’t to be mountainous?
  • To what extent does the geological structure of the mountains and the flatter land help make Singh’s approach successful? The upper layers there are alluvial.

The usual criterion of repeatability or replicability: Singh did achieve repeated success in other villages too. In fact, in hundreds of other villages—800+ villages, in fact! Good! No, Great!!

Still, notice, all these villages lie in the same region—a comparatively very small part (area-wise certainly less than 5%) of the entire state of Rajasthan. Did Singh, especially after the Magsaysay award (2001), try something about 400 km west? at least about 200 km west? Why not?

Why does the media still insist on saying that it was a success in the arid lands of Rajasthan—as if all the representative parts of Rajasthan had been successfully demonstrated to benefit from the scheme?

In summary: Singh did demonstrate the very feasibility of this micro-level approach, going against the then existing engineering wisdom. Congratulations! Singh also did replicate his initial success at hundreds of other locations in Rajasthan—though not at a majority of places—or even a representative minority of places—in that state. Our optimism should be guarded. [Also, though I didn’t mention it, observe the government tried to spoil Singh’s work. When governments enter the economy, they are like that, regardless of who peoples the government.]

2. Anna Hazaare’s “Work” in Ralegan Siddhi:

Ah, Anna Hazaare! … I have written about this fellow before. Regardless of that, let me say, it’s impossible to hold a lasting grudge against this guy. The main reason is that one doesn’t hold grudges—there is no need to do that if you are willing to pass your moral judgements. The other reason is supplied by his personality: his appearance, mannerisms, language, “thoughts,” actions (remember him running after breaking his fast in Delhi?)… All such things included. …

… Hazaare’s is a personality of a very exceptional kind: he is a walking & talking, breathing & living, caricature. And he also is very forceful about what he does. … A forceful 3D living caricature that is busy building castles in the thin air at all times. How would it even be possible to take him seriously? Not unless the media makes an elephant out of him, and then insists on using the TV to make it sit in the room—your living room.

But let’s keep that aside, and let’s try to look at his water-conservation “work” in Ralegan Siddhi. How successful has the effort been, given its geographical and other contexts? A few notes of mine follow:

What is the extent of the greening that has been effected in Ralegan Siddhi? How does it compare (keeping all other factors equal or comparable) to the average greenery within an area of 50 km radius? Or even the other drought-prone region right in the same district? Answer: not at all impressive—if you are an honest observer, that is.

If Hazaare were not to arrange to divert water from the conventional irrigation canal running nearby to Ralegan Siddhi, if he were to rely only on his local, micro-level, water conservation schemes, how successful could he have been? About 25–30%, at the most, of what you presently see there, some engineers estimate. If he now were to agree not to take any water from the nearby Kukadi project canal, how long would it take for the existing Ralegan Siddhi greenery to turn yellow/brown? My estimate, after discussions with some engineers: about 5 to 10 years, with the lower side being much more likely. Note, this is a period far shorter than the one for which Hazaare has been continuously lauded in the media (and in the successive state governments) for his water-conservation “work.”

Replication: The Maharashtra government has wasted 100+ crores on this “Gandhian”‘s hopeless dreams. Why couldn’t they achieve success anywhere else—not at a single site elsewhere? Hazaare’s and media’s answer: It’s all Maharashtra government’s fault. (LOL!)

Note, Singh did succeed in hundreds of other villages—initially (and for a long time), without taking a single penny from the government funds. Hazaare did not succeed in a single other village, despite hundred+ of crores.

Summary: Idiocy, hypocracy, and media hype. Plus, shameless loot of the credit actually due to the conventional irrigation engineering.

3. Suresh Khanapurkar and Amrishbhai Patel’s work in Shirpur:

OK. With sections 1. and 2., we are already done with the notable works done in the 20th century. Both were (or at least have been called) “Gandhian.” Now, we enter the 21st century, and the matters do get a bit more more complicated—also, better funded, better documented, and on the whole, more interesting, anyway.

Summary: Khanapurkar is a geologist, and has retired from a government job. He has been an RSS guy. Amrishbhai Patel always has been an Indira Congress guy, an MLA too. But, he is a Patel. [Aakar?] As to their work: as (almost) always (at least in Maharashtra), when it comes to some secular/non-religious kind of a social work, first, someone from the Congress leads the way; if successful, The Family is given the entire credit; then, the “jholawaalaa”s eagerly follow; then some RSS guy enters the scene and attempts some improvement on the original theme, which often is unsuccessful, or at least, it is not just as successful; then the pinkos use the RSS guy’s failure to attack the RSS; then the RSS/RSS guy make(s) deal with the government/local powers; around this time, the RSS recedes into the background and the RSS guy finally begins to shine in the limelight; then more funds follow; then some more critical “jholawaalaa”s follow, and, simultaneously, the other pinkos and the reds wait and watch.

With the pressure of providing a very short and succinct summary being out of the way, we may now look at the situation from the engineer’s perspective.

While covering Hazaare’s “work,” I did not care to provide any link. The resources are over-abundant, and, as expected, none covers the ground reality the way it should be. For example, none discusses the extent of contribution of the Kukadi project canal; none mentions the hundred+ crores already wasted by the successive Maharashtra governments on Anna’s day-dreams “thoughts.”

In contrast, for the Shirpur pattern, there is an objective need to provide links. Reasons:

  • The Shirpur pattern has been tried elsewhere with some success, e.g., at the initiative of the NCP in the drought-prone areas in southern Maharashtra.
  • There is a BJP government in the Center, and a BJP-led government in the State.
  • The new BJP budget at the Center has announced thousands of crores for micro-level water-resources management: Rs. 5,300 crores nationwide, i.e., about 850 Million US dollars—say, almost a billion dollars.
  • The Shirpur pattern is open to a critical scrutiny, and not just of the same kind as Singh’s work invites, viz., the relevance of the geological factors, and the feasibility (perhaps with local adaptations/changes) or otherwise of replication. In addition to those two factors, the Shirpur pattern also remains open to an additional serious criticism, one concerning the undesirable and highly under-appreciated side-effects. And, this point acquires urgency because of the first three points.

Hence for the Shirpur pattern, I sure wish to provide at least some links. These follow, with a few notes of mine:

Here is a typical introductory sort of an article on this topic that would appear before the state/central governments began supporting the idea: [^]. I anticipate that much better written (and better-formatted) articles would arrive in the near future.

The model seems to work also elsewhere: [^].

Again, a perceptive piece, despite the fact that it seems to come from someone with pinkish inclinations: [^]. The author for the preceding piece is one K. J. Joy [^]. His name means that he must be at least a pink if not a red. [Aakaar?] He is something of that sort! “Privatization can do more harm than good” [^]. OK. Humour apart, even if his understanding of the terms such as “rights” (i.e., more properly, “individual rights”) and “privatization” does not seem to be sufficiently clear, it still does not mean that his article itself isn’t studious or valuable. Do go through the article; highly recommended.

A well-informed criticism; note especially the important and relevant geological points: [^]

An article that cites some actual geological data. Though the data are far too coarse-grained to be of any direct use in any micro-scale schemes, the article at least cares to look into some factual data. … You are not surprised by the author’s background, are you? [^]

An indication of the kind of complexity there is, in implementation: [^]

An example of the usual “our region didn’t get its share” [^]; such things seem to have begun already! Note, the demand has been made without pausing to think anything about whether or how the approach might at all work in a given area. I am not saying that the approach wouldn’t work in Marathwada—another region of severe droughts. In fact one of the links I gave above already indicate some success for this approach in that region too. Here, I am just highlighting the kind of artificial tensions that come in whenever governments interfere with the economy. And, I am saying, without being cynical about anything: “more research is necessary.”

4. A word about my planned research:

Here is an outline of the way my planned research might go:

  • Initially, (i) build a computer model of the surface topology and the underground geological strata and structures for some area—this could even be an imaginary geographical area!; and then, (ii) develop/adapt algorithms to simulate groundwater seepage after precipitation in this area, running the simulation for, may be, a decade or so. The quantities for the precipitation and the surface flow would enter the model simply as assumed boundary data, that’s all.
  • Add features to incorporate small check-dams or other structures at various locations and scales, and study their effect on groundwater seepage and water-table levels.
  • Add the features of the surface water flow and study aspects such as flooding vs. seepage, etc.
  • Then, take a focus area—an actually existing drought-prone area—and study its precipitation and geological features, build models, run simulations, and make some recommendations for locations of check dams and other structures/features.

The above is a broad conceptual outline that I currently have in mind. In the actual research, some components of some of the steps may get mixed up, and some other steps may get added in, e.g., a step of: simulating the effect on groundwater seepage and water-table levels, due to closure of an aquifer that got exposed due to digging of deep trenches while implementing the Shirpur pattern.

The research should actually begin after I land a professor’s job. In the meanwhile, enthusiastic engineers with programming knowledge may feel free to approach me—but only if they are willing to work hard, and for free! … When I play, I play, but when I work, I really work. Usually, that means hard work, at least compared to many, many others. So, don’t approach me unless you already know what it takes to do hard work over a considerably long period of time—at least months. (As far as I know, no smart work ever comes before at least a certain quantum of some very hard work has gone before it.) Also, I have no money to support you—or, for that matter, as of today, even myself! But if it still is all OK by you, and you still wish to do something in this direction working with me, then do feel free to drop me a line. Use email or comment form (and feel free to mention that you want to keep the comment confidential—comments here are moderated). I am serious about this stuff.

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A Song I Like:
(Hindi) “yeh shaam mastaani…”
Singer: Kishore Kumar
Music: R. D. Burman
Lyrics: Anand Bakshi

[I guess the post already is in a fairly good shape. I would update it only if I find some more interesting links etc.; otherwise, I would leave it alone as is. I mean, adding updates for streamlining and clarifying are much less likely here. Anyway, bye for now… ]

[E&OE]

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