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Rainwater collection, on smaller and larger scales


ScienceNostalgia101
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So recent events got me thinking about the politics that led us here, including the 2016 election and Martin O'Malley's so-called "rain tax". It taxed impermeable surfaces that cause water to pick up pollutants as it flows, and further damaged his already not-so-hopeful career. While Vox is defending this tax (or at least criticizing flawed criticisms of it); and I get realize that there is often more to these issues than some buzzword will let on; what I am wondering is why there wasn't infrastructure in place; whether on a local or federal level; to actually collect rainwater so it could be transported to where it could be used. Seems a waste to just let some mere lawn absorb it in the first place. While I'm not sure whether rainwater is clean enough to drink (although I'm pretty sure small amounts of it have gotten into my coffee cups from time to time), it sure is desalinized enough to be useful for farming. Why not have a network of concave-up ellipsoids and/or half-pipes over and around houses to collect the rainwater, and a network of rainwater-pipes that provide water that's suitable for everything short of drinking it?

 

On a larger scale, why not put a concave-up ellipsoid over the sections of the Atlantic and/or Pacific oceans that are directly underneath the intertropical convergence zone? That way, you can pump or siphon water from these ellipsoids into a network of on-shore rainwater reservoirs, as well as reducing the severity of hurricanes by the fact that their freshly fallen rain has fallen not into a deep ocean but to a comparatively shallower pool from which some of the water is already starting to be drawn out. Or am I missing something here?

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42 minutes ago, ScienceNostalgia101 said:

So recent events got me thinking about the politics that led us here, including the 2016 election and Martin O'Malley's so-called "rain tax". It taxed impermeable surfaces that cause water to pick up pollutants as it flows, and further damaged his already not-so-hopeful career. While Vox is defending this tax (or at least criticizing flawed criticisms of it); and I get realize that there is often more to these issues than some buzzword will let on; what I am wondering is why there wasn't infrastructure in place; whether on a local or federal level; to actually collect rainwater so it could be transported to where it could be used. Seems a waste to just let some mere lawn absorb it in the first place. While I'm not sure whether rainwater is clean enough to drink (although I'm pretty sure small amounts of it have gotten into my coffee cups from time to time), it sure is desalinized enough to be useful for farming. Why not have a network of concave-up ellipsoids and/or half-pipes over and around houses to collect the rainwater, and a network of rainwater-pipes that provide water that's suitable for everything short of drinking it?

 

On a larger scale, why not put a concave-up ellipsoid over the sections of the Atlantic and/or Pacific oceans that are directly underneath the intertropical convergence zone? That way, you can pump or siphon water from these ellipsoids into a network of on-shore rainwater reservoirs, as well as reducing the severity of hurricanes by the fact that their freshly fallen rain has fallen not into a deep ocean but to a comparatively shallower pool from which some of the water is already starting to be drawn out. Or am I missing something here?

Well we've had water butts for centuries, to collect run-off from roofs. But run-off water won't generally be suitable for drinking, because of what is on the surfaces it runs off.

And some countries, or areas,  have sewer systems that keep rainwater run-off separate from waste water. So there is exactly the infrastructure you are talking about in some places. Here's an example (N Ireland) https://www.nidirect.gov.uk/articles/connecting-your-home-right-drains

 

 

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2 hours ago, ScienceNostalgia101 said:

Why not have a network of concave-up ellipsoids and/or half-pipes over and around houses to collect the rainwater, and a network of rainwater-pipes that provide water that's suitable for everything short of drinking it?

Many of the homes I visited in Germany had the gutters designed to drain into a single downspout in the backyard, and that led to a series of catch-barrels. All of these homes had veg gardens, and the owners used rainwater exclusively for gardens. I was so impressed that I looked into something like it in the US, and found that my municipality doesn't allow homeowners to retain rainwater in any way. I still don't understand why, but apparently they fear people would hoard it so much that it would stop raining and filling the reservoirs. Or they could be greedy.

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30 minutes ago, ScienceNostalgia101 said:

I've also heard of local laws against using front yards as vegetable gardens. Makes me wonder how much money public officials have accepted from the agricultural industry.

Laws like that may be tied to commerce. Iirc, in the US we can grow veg for our personal consumption on just about any property we own. Trying to sell it to others is a whole different kettle of corn.

 

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2 hours ago, Phi for All said:

Many of the homes I visited in Germany had the gutters designed to drain into a single downspout in the backyard, and that led to a series of catch-barrels. All of these homes had veg gardens, and the owners used rainwater exclusively for gardens. I was so impressed that I looked into something like it in the US, and found that my municipality doesn't allow homeowners to retain rainwater in any way. I still don't understand why, but apparently they fear people would hoard it so much that it would stop raining and filling the reservoirs. Or they could be greedy.

What? You mean it's illegal to have a water butt connected to the gutter on your roof? Surely not. Where is this?

I have one because I have camellias, which don't like the high pH of London water, coming as it largely does, from chalk hills. Very useful in dry weather.  

2 hours ago, ScienceNostalgia101 said:

Your own source says "to a river or beach", not "to a farm." I was wondering what infrastructure exists to redirect water that's clean enough for farming, but not clean enough to directly ingest, to farms.

Oh I see. I have not heard of that, but it could easily be done, once one has the dual sewer pipework system installed in the community. (The example I gave was from N Ireland, where it rains all the bloody time, so I suppose they just want o get rid of it! )

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26 minutes ago, exchemist said:

What? You mean it's illegal to have a water butt connected to the gutter on your roof? Surely not. Where is this?

Central Colorado, USA. I just looked up the current restrictions, and it looks like they've had to change their tune and allow folks to retain up to 110 gallons of rainwater in no more than two barrels for gardening only. The new laws went into effect last August. This state has a history of claiming water rights over neighbors who obtained statehood after we did, and that's led to some bizarre water laws.

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32 minutes ago, Phi for All said:

Central Colorado, USA. I just looked up the current restrictions, and it looks like they've had to change their tune and allow folks to retain up to 110 gallons of rainwater in no more than two barrels for gardening only. The new laws went into effect last August. This state has a history of claiming water rights over neighbors who obtained statehood after we did, and that's led to some bizarre water laws.

Gosh that is weird. So 2 x 55USG barrels.  But that's fair bit. I just have one barrel, but my garden is not a big one.  So far as I know I can have as many as I like. In fact we are all encouraged to use rainwater, since if we don't it all goes into the main sewer (no dual system in London) and in heavy rainfall that creates problems for the waste treatment plants.  What we do sometimes get is a hosepipe ban in summer if water is short. As such times a water butt is very handy. 

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7 hours ago, ScienceNostalgia101 said:

what I am wondering is why there wasn't infrastructure in place; whether on a local or federal level; to actually collect rainwater so it could be transported to where it could be used

You don’t have this? 

Water around where I live gets transported to the Potomac and feed the washington aqueduct. Some parts of the storm drainage system are combined with the sewer system, some are not.

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In Singapore it is illegal, because of mosquitos and malaria. Here in Australia rainwater is commonly collected and used for both household and garden use and usually tanks have mesh to discourage mosquitos (but unless well maintained, not always preventing their larvae getting in). Most of our own personal household water supply is water collected from our roofs, but we are rural, outside any municipal water supplies. Some places there can be reasons to avoid them - eg having big overhanging trees with bird and fruit bat populations can make the water unsafe to drink.

There were widespread restrictions on household tanks in urban areas in the past, in part to support the viability of municipal water supply systems. Roof and other rainwater runoff is usually directed to "stormwater" drains that (usually) feed directly into creeks and rivers. Increasingly with some "pits" to catch rubbish. Oil, rubber and other contaminants etc off roads isn't separated. Of course when there are floods waste of all kinds ends up in floodwater.

Rivers are most often the source of irrigation water for farms, without any specific water collection or diversion; specific collection tends to be on-farm (earth dams) or part of larger irrigation schemes, based around existing rivers and catchments and dams.

Economics is probably the biggest impediment. Water isn't often diverted large distances unless part of larger schemes, like the Snowy River hydroelectric diversion of coastal flowing water inland, in combination with the Murrumbidgee Irrigation Scheme built around those flows. Even now it is unclear whether such schemes (minus the electricity) were ever cost effective but psychologically they were and are reassuring to have in a nation with climate that swings from extremely dry to wet and back again; political careers have been bolstered by vocal support of grand schemes that have been repeatedly shown to be unrealistic and economically wasteful.

Agriculture is usually where it is because it has the soils, the climate, the rainfall, the rivers so additional water resources like urban rainwater runoff, that need a lot of investment and infrastructure to be useful are rarely that significant.

Unrealistic and economically wasteful is why catching and diverting urban stormwater to rural irrigation isn't done.

Edited by Ken Fabian
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7 hours ago, Ken Fabian said:

In Singapore it is illegal, because of mosquitos and malaria. Here in Australia rainwater is commonly collected and used for both household and garden use and usually tanks have mesh to discourage mosquitos (but unless well maintained, not always preventing their larvae getting in). Most of our own personal household water supply is water collected from our roofs, but we are rural, outside any municipal water supplies. Some places there can be reasons to avoid them - eg having big overhanging trees with bird and fruit bat populations can make the water unsafe to drink.

There were widespread restrictions on household tanks in urban areas in the past, in part to support the viability of municipal water supply systems. Roof and other rainwater runoff is usually directed to "stormwater" drains that (usually) feed directly into creeks and rivers. Increasingly with some "pits" to catch rubbish. Oil, rubber and other contaminants etc off roads isn't separated. Of course when there are floods waste of all kinds ends up in floodwater.

Rivers are most often the source of irrigation water for farms, without any specific water collection or diversion; specific collection tends to be on-farm (earth dams) or part of larger irrigation schemes, based around existing rivers and catchments and dams.

Economics is probably the biggest impediment. Water isn't often diverted large distances unless part of larger schemes, like the Snowy River hydroelectric diversion of coastal flowing water inland, in combination with the Murrumbidgee Irrigation Scheme built around those flows. Even now it is unclear whether such schemes (minus the electricity) were ever cost effective but psychologically they were and are reassuring to have in a nation with climate that swings from extremely dry to wet and back again; political careers have been bolstered by vocal support of grand schemes that have been repeatedly shown to be unrealistic and economically wasteful.

Agriculture is usually where it is because it has the soils, the climate, the rainfall, the rivers so additional water resources like urban rainwater runoff, that need a lot of investment and infrastructure to be useful are rarely that significant.

Unrealistic and economically wasteful is why catching and diverting urban stormwater to rural irrigation isn't done.

Excellent point about the mosquitos - I was forgetting that. I seem to recall in Dubai we weren't allowed to have any standing water in gardens, apart from swimming pools that were treated and circulated. Even in London, in a water butt with a lid on it, I find I get quite a few mosquito larvae in it, in summertime.

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14 hours ago, exchemist said:

Excellent point about the mosquitos - I was forgetting that. I seem to recall in Dubai we weren't allowed to have any standing water in gardens, apart from swimming pools that were treated and circulated. Even in London, in a water butt with a lid on it, I find I get quite a few mosquito larvae in it, in summertime.

Are you referring too Mosques in a negative connotations? Like the Synagogue? 

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I forgot to account for the issue of standing water attracting mosquitoes. Would putting wire mesh in and/or above the rainwater collectors be at least somewhat of a deterrent? Even if so, would there be the issue of the mosquitoes coming for the standing water, and staying for the readily available humans when they can't get at the standing water? Conversely, if the wire mesh were to be barbed, would one be able to attract mosquitoes to the standing water only for them to impale themselves on the barbs and therefore reduce their population to that comparable or lesser than what it would be were the rainwater not collected?

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4 hours ago, ScienceNostalgia101 said:

I forgot to account for the issue of standing water attracting mosquitoes. Would putting wire mesh in and/or above the rainwater collectors be at least somewhat of a deterrent? Even if so, would there be the issue of the mosquitoes coming for the standing water, and staying for the readily available humans when they can't get at the standing water? Conversely, if the wire mesh were to be barbed, would one be able to attract mosquitoes to the standing water only for them to impale themselves on the barbs and therefore reduce their population to that comparable or lesser than what it would be were the rainwater not collected?

You could use a very fine mesh over any openings, known as mosquito netting. The mesh size needs to be 1mm or less - and, therefore, so do any gaps where the mesh is attached.

Mosquitos (the females) feed on blood, in order to get the nourishment they need for egg production. Human beings are not an alternative to water for them.

Insects do not impale themselves on barbed wire, as a rule. 

 

Edited by exchemist
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Is there any way to make the barbs made of something see-through that the mosquitoes may mistake for standing water? As in, that they think they're flying into standing water but they're actually flying into sharp objects blocking the standing water?

 

Presuming it's put out of reach of human beings who'd make the same mistake. Or at least with warning signs posted nearby...

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21 hours ago, ScienceNostalgia101 said:

Is there any way to make the barbs made of something see-through that the mosquitoes may mistake for standing water? As in, that they think they're flying into standing water but they're actually flying into sharp objects blocking the standing water?

 

Presuming it's put out of reach of human beings who'd make the same mistake. Or at least with warning signs posted nearby...

Insecticide impregnated mosquito nets work well where humans are the attractant. Impaling is not an effective way to kill mosquitos. A lot of thinking and a lot of work has already gone into mosquito control; better to review what has already been done before attempting new and unusual methods.

Mesh works quite well to keep mosquitos out of water tanks but it requires good design, construction and ongoing maintenance (cleaning mostly) as well. We usually have a mosquito proof strainer set into the top of water tanks, but there can be gaps if not screwed down. But leaving them not screwed down makes lifting them out and emptying accumulating leaf and other debri easier, so they often aren't. Also the overflow outlets have mosquito mesh - but can get clogged, so the water level can sometimes rise above the level of the (sunken) strainer. Mosquito eggs laid in that water can be small enough to pass through - which isn't a problem so long as there is no way for an emerging adult to get out.

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