# Catching Rainwater in a Safe and Efficient Manner?

There is a world out there, with people fairly like us (minor physical distinctions, irrelevant to the question), and with technology on par with ours, but with a very different religion.

The world (unified government) has this state religion. This religion is

• Based around water
• Good-versus-evil
• 'Good' deity lives in sky, 'bad' in the ocean
• Purification rituals are performed with holy (rain) water
• State church dispenses rituals
• Very lucrative - the ritual includes a tithe
• Tithe amounts to about $50 a year per person, consuming about 3 liters of rainwater a year per person The government, in an attempt to increase profits, has set itself on the task of collecting more rainwater - more money! However, attaining enough rainwater to support the world population of 9,000,000,000 people is understandably difficult. So, the solution is determined to be a vast rainwater collecting scheme. The location on the planet, with similar ecosystems to earth, and a similar rainfall capacity as earth, has not been set - the scheme could be anywhere or everywhere. Similarly, the method has not been decided upon. Most importantly, the maximum amount of rainwater is to be delivered to cities, at distances of 250 km in rainforests, 100 km in temperate climates (prairies, deciduous forests, etc), 150 km in snowy climes, and 100 km (on average) from any other climate. No one should be harmed - that is bad publicity. The next goal (and the one the government is most willing to give up) is to hide the operation - there is a minute chance of people losing faith. But that faith can be recovered. As such the goal is expendable. Finally, the lowest cost in an economic system similar to ours is also a minor but desirable goal. All in all, how might a government attain the greatest amount of rainwater, transport it with minimal loss in both rainwater and money, and deliver to cities at specified distances, all safe, cheap, and (hopefully) hidden? Note Desalinating seawater is out of the question - tainted by the evil deity. Note If rainwater touches the earth or any water that touches the earth it is rendered groundwater, however certain pools can be blessed if they are artificially constructed and do not touch the ground. • How expensive is rainwater? How much would one glass of it sell for, in Earthly currency? Feb 24, 2017 at 14:51 • Eh.... quick question: when does rain-water stop being rain-water and become ground-water? When does ground-water stop being ground-water and become tap-water? When does tap-water stop being tap-water and become bottle-water? And so on. The most critical question would probably be: when does rain-water become pond water, because that is how rain-water is traditionally collected: into large ponds. Click for rainwater catcher on the island of Lokrum, Croatia. Grey is the gathering surface, smooth blue below is the pond. Feb 24, 2017 at 15:03 • @WillowRex I'm sorry if it was unclear, the 3 liters of rainwater is for religious purposes only.It is the equivalent of communion wine. They drink simple purified water for daily purposes, like is done in developed regions of the various countries of Earth. Feb 24, 2017 at 16:36 • @ggiaquin It might be a scam, the reality-check is for the feasibility of collecting water with the conditions above, not for the feasibility of the religion. Feb 24, 2017 at 16:52 • @N2ition I apologize, I looked over the statement and found an autocorrect line underneath fluoride. I intended to write chloride. My autocorrect does the strangest things. And thank you, natural poison detection sounded like an interesting idea when it occurred to me- low resistance, high detection. Feb 25, 2017 at 16:47 ## 9 Answers The requirement is for 3 liters (0.003 m$^3$) per person per year. New York City has 783 km$^2$surface area (or 783000000 m$^2$) and gets about 1.2 meters of rain per year. 8 million residents need 3 liters each for 24,000 m$^3$of water. If we catch all of the available rainwater, then we need 24000 m$^2$or 0.024 km$^2$or 0.003% of the surface area of the city to be covered by water catchments in order to provide enough rainwater. 24000 meters is about 4 football fields, so, for example, Yankee Stadium and Shea stadium with some cisterns dug below them would be able to collect the needed rainwater over the course of the year. In other words, in NYC, one of the densest places in the world, this is a trivial amount of area needed to catch the rainwater we need. Even if you drop the rainfall to Phoenix or Baghdad levels, you just don't need much are to catch 3 liters per person. Now Cairo or Lima or someplace where it literally never rains will be a problem, but given your world religion I'd be surprised if anyone lived in such places. • This is an excellent possible answer for the 'where' part of the question, as well as an interesting commentary on volume, but please answer more portions of the question in your answer in order to conserve space. Thanks for your answer! Feb 24, 2017 at 15:24 • @Imperator I guess my point is, why would governments go to all that trouble, when they can collect more than enough water for people within the city limits. Imagine Yankee Stadium or the Rose Bowl as giant temples to the rain god. Cities would just have these temples scattered around, and these temples would provide enough water. No need for aqueducts or whatever. Feb 24, 2017 at 15:31 • Yes, that would be a possibility, but the three liters a year are spread out over various ceremonies. As such, the supply would have to be constant. And when it comes to city builders, Brasilia, the capital of Brazil, is a very recent city, compared to others of comparable size, and is recent because building cities in rainforests is of a greater difficulty than imagined. It would be far easier to simply collect water there, and not go to the trouble of constructing a city. Also, cities are fairly large, so you would have to continually support a city of 20,000,000 people. Feb 24, 2017 at 15:49 ### Leave a clean bucket outside. Three liters of water per year isn't very much. Even an area like Phoenix, AZ, which located in a desert, if you're not familiar with the city, receives over 20cm of rainfall per year. A liter is 1000$cm^3$of water, so collecting enough rainwater for a single person would only require catching the rain that falls in a 150$cm^2$area. A standard 5-gallon bucket, in comparison, has a bottom surface area of over 500$cm^2$. Collecting enough water in a place like Phoenix would be as simple as each person placing a bucket outside whenever it looks like it might rain. Rainwater is fairly clean, so as long as everyone keeps their rain buckets clean, it wouldn't even be necessary to filter the water. That calculation is for a desert. Any other environment would make it even easier to collect enough rainwater, so you won't need to transport anything long distance, regardless of where your city is located. As this is a religious rite, it's highly likely that people won't be using actual general purpose buckets for their water collection. Each individual in your world probably owns a ritual water collection device that they leave outside to catch rain. The water from these collectors would be brought inside after each rain and added to a sealed storage container to prevent water loss due to evaporation. • That could work, however, that level of publicity might be problematic- if you can get rainwater yourself, then why pay the tithe? Feb 24, 2017 at 16:53 • One issue with Phoenix XD. Since I am actually from Phoenix, I can expand on this a little... the dust storms that happen before the rain fall almost always muddy any body of water such as pools outside. A bucket would almost certainly be half filed with sand/mud. Feb 24, 2017 at 16:54 • @Imperator Rainwater is easy to collect, even by accident, and it's difficult to keep the fact that it's raining a secret. It would make more sense for people to collect their own rainwater, and then pay tithes out of piety, like members of most churches on Earth. Feb 24, 2017 at 16:57 • @ckersch Yes, that has occurred to me, and I am attempting to come up with a creative answer (I might even pose it on this site), I just know that the collecting of rain is an important aspect of the story, so I opted to post this question first. In addition, the water would probably need to be dispensed by the church for the same reason Christians go to communion, not just take a shot of Merlot and a eat hunk of rye- it is believed to have a mystical property imparted by the ritual that accompanies it. Feb 24, 2017 at 17:01 • The people must periodically take their ritual water collection devices to the local priest to get them blessed and purified. A tithe or levy in exchange for this service is strongly encouraged. Feb 25, 2017 at 1:54 On our world we already have the means in almost all climates to do this with minimal alterations to our infrastructure. Existing roof gutter systems that simply discharge in to a 55 gallon barrel are common. I can even go buy one for about$100 at a local hardware store and install it quickly and easily. Mandate your churches to build steel roofs that are somewhat over sized with a simple but robust rainwater catchment system. In Kansas I could easily fill a 55 gallon drum from one side of my roof in a year, so It should be pretty easy to catch enough for the congregations' needs and have surplus to ship to the dryer climates.

A fun thought would be to increase revenue with "holy" gardens that take advantage of all that rainwater and sell the produce. A contained and blessed greenhouse elevated above the ground and using holy rainwater at each church could work. How about a holy Tomato, or some blessed Zucchini?

• Heh. Reformation opposing the Holy Vegetables. Led by Martin Tuber, maybe? Feb 24, 2017 at 18:36
• Well played, sir! Well played! Now, would Martin tuber be excommunicated with a papaya bull? Feb 24, 2017 at 18:38
• Possibly. Although when the peasants revolted, would the heirlooms they discarded be tomatoes or antiquities? Feb 24, 2017 at 18:40
• HA!...they would be tomatoes as long as the church was based in Roma. Feb 24, 2017 at 18:42
• Maybe the revolt could be based in CuCumberland. Or the diet of worms was in fact a paleo diet rejecting agriculture. Feb 24, 2017 at 18:44

First, the word tithe means "a tenth." From your example, if the tithe holds, it would indicate that the average income is $500 a year, and your world is in extreme poverty. You may have meant a more general offering, which would not be tied to a percentage of income. Remember, the cost of any good is based upon its scarcity. If the holy water is too abundant, the price will fall. Therefore, it is wise to keep the supply limited to encourage a higher price. Build a temple next to the sea. Scared fires burn below a brass container, filled with seawater. The heat evaporates the water. The temple complex funnels the water vapor such that condensates 'rains' down upon the sacred pools. The government can offer pilgrims access, for a price, can have services in the temple and allow faithful to throw lists of their sins in the scared fire. • Interesting take, and I do appreciate that level of pedantry, it is often my position, however travelers would not agree to go to a temple near the evil sea. Feb 24, 2017 at 18:11 Create catch basins in areas of high rainfall and aqueducts and canals to transport it. Then bless them to make them holy. Heck, if the Pope could declare the nutria (beaver) in Quebec and capybara in Venezuela to be fish so they could eat it on Fridays during Lent (Scientific American), there's not much else they can't justify. In southeast Asia, satellite photos have identified a large number of overgrown catch basins and man made water collection pools from previous civilizations. Looking that up may give you more ideas for your civilization. Another method would be to have every building build catch basins on their roofs as a show of faith. Of course, the basins would have to be properly blessed (for$) and the rainwater donated so it could be distributed by the church.

# Blessed pool, sand bed

Actually there are lots of way to purify water by simple means. A common method is sand filters. This will give you safe and storable water. If you want to increase the shelf-life, store the water in PET bottles and leave them out in the sun for 6 hours.

Your only concern is the "legal" matters. And in your comment you said you just bless the pools by doing so it "legally" remains holy rain-water. Well there you have it then: blessed collection surfaces, blessed storage pools and sand beds, store in transparent bottles and made safe by sunlight.

• Sand is a bit close to earth for my liking, but it is a significant possibility. Thank you! Feb 24, 2017 at 15:18
• Grind stones to sand. :) Feb 24, 2017 at 15:21

From what you have written, I am assuming that 3 liters of rainwater are worth \$50. This implies that the cost of collecting 3 liters of rainwater + filling (in bottles/drums) expenses + transportation expenses over a distance off 200 km should stay substantially lower than \$50.

The obvious first step in the scheme of things is collection of rainwater. This will obviously require artificial, blessed pools. The larger and higher the pool(s), the better. This could be especially helpful in cold regions where snowfall (thus, heavenly water) helps collects large amounts of snow. In the mountainous regions, you would want to build high dams for snowfall collection. The snow can later be transported to warmer regions where it would melt into holy water.

The construction of blessed dams would cost you a lot initially, but considering the exorbitant income, each dam would easily pay its price in 3-4 years if not earlier.

For rainforest and plain habitats, you would have to build blessed reservoirs. These would be large collecting vessels which would be covered with gigantic lids once rain stops.

You would want to keep the source (where rainwater is collected) and destination (where rainwater is dispatched to) places as close as secretly possible. For example, you might want to build one blessed reservoir in the middle of 5 cities, in a large, barren patch, 50 km from the nearest city. From here, you can transport the rainwater in bottles to all cities and decrease the distance substantially.

The initial set up will be costly. No mentions of cost restrictions so I will assume that cost is not a factor in setting up the gather points. Something to keep it "appearing" natural would be creating a reservoir that looks like a natural lake. Keep the water outside of the city, so that the only way people MIGHT find it is if they are really going off into the distance... but even still it would be ground water so they would see it and know they can't touch. You don't want to add any facilities to it such as pumps and fences. This would make it seem really suspect especially in the middle of nowhere. So let it appear to be natural. Then have a truck with pumps come by like gas trucks, suck up the water to fill the tank and off they go to the delivery point. Nothing would seem odd about it because these trucks come by anyways for delivery. If you are worried about the increased truck traffic, have the bulk be done at night when most of the people are sleeping.

Oh and one other point to do about the fake lake is that the bottom/material used to shape the lake would be specially made to keep the water from being contaminated so it stays as rain water and not ground water.

You can also design ways to capture water from the roof of churches. Have funnels drip the water down into tanks in the church where the church can then use to distribute. Since this place seems to be highly centered around church, there should be a ton of churches every where. Combine that with a few fake lakes around the outskirts and there should be a fairly decent amount of water coming in.

Rainwater Harvesting initial setup is costly but one time setup is not much worth of it.The main reason of keeping the rain water preserved is the ponds, channels, ditches, canals, etc. is to recharge the groundwater with this surplus unused water. This conserved water is lifted up with the help of deep or shallow tube-wells to be used as drinking water or to be used in agriculture.

• Hi, welcome to worldbuilding! This might explain how it works in small scales, but it fails to explain the exact details required to answer the question - would you be able to edit your answer to explain how this works given all the constraints of the question? Thanks Aug 23, 2017 at 8:30