Anyone who has followed this blog through most of its existence will be aware that I started it during the initial stages of a local water resources study initiated by the City of Tucson and Pima County - where I live. This was a 20 month, two-phase, multi-disciplinary, multi-agency effort to catalog our existing water resources, water and wastewater infrastructure, and existing policies for managing those resources; followed by a discussion of recommended policy changes that could help ensure sustainability of those resources as this area continues to grow. Those recommendations were contained in a Phase II report that was issued in December of last year.
On Jan. 12, the City Council and the County Board of Supervisors held a joint meeting where they considered a resolution to accept the Phase II report and commit to following through on its recommendations. At that time the county voted to endorse the report but the the city, expressing reservations about the content of the report and the process of its creation, voted to continue the comment period for another 30 days then revisit the resolution.
Last week the city council (the paper incorrectly reports that the council approved the study, but all they did was agree to reconsider the resolution next week) held a study session and a public hearing on the report, which were well attended by both proponents and opponents of the report findings. Some on the city council are very concerned about recent charges that city government is unresponsive to the needs of the business community and that posture is stifling economic growth in the city. They point to the current slump in the development industry as evidence of those charges and insist that loosening up some of the regulations on development would spur this industry and restore the sort of economic growth we experienced during the years immediately preceding this current slump. This argument is preposterous (in my opinion, but I think it's a well-supported opinion) because the city policies and regulations regarding development were pretty much the same during the go-go years as they are currently AND the city has been looking at suspending a number of fees during the current slow-down.
The development folks are also pointing to a current policy (as I discussed here) recently enacted by the city to deny extension of water service to areas outside the current service area of the water utility unless there is a legal obligation to serve that area. They claim that there are many developments that would be moving forward if only the city would agree to provide water service. This is purely a bluff. There are other water providers in the area noted that could potentially provide water service (although there may be greater infrastructure needs for those utilities) if these development really were "shovel-ready", but I doubt they actually are.
This is basically a situation where our political leaders have to make a choice between serving the short-term economic needs of the community or caring for the long-term sustainability of the region. If you understand politics like I do, you'll understand why I'm worried about the prospects for full approval of the report. But they may yet surprise me. I'm hopeful that they will, but prepared to be at least a little disappointed.
Saturday, February 13, 2010
Wednesday, February 3, 2010
Give us more water ... or the aquifer gets it!
This is just priceless.
A farmer from the Central Valley of California makes the argument, in an opinion piece for the Modesto Bee, that if only the Delta restrictions could be dropped, allowing more surface water to be delivered to farms, they could stop overpumping the aquifers - resulting in subsidence, diminished water quality, and wholesale dewatering of their insurance supply.
Come on guys. Are we really supposed to be sympathetic to your plight? OK, you're behaving rationally under the circumstances because the State of California has chosen (start at p. 8) not to govern in the case of groundwater use, but you could still choose to manage the resource more wisely by setting up local governance that actually collects some data on groundwater use, sets some pumping limits, and tries to avoid some of the external costs of over-pumping. But no, this is just another lame opportunity to whine about the Delta smelt and how the little fish is harming farmers.
Time to move on.
Once again, thanks to Aquafornia for bringing this to my attention.
A farmer from the Central Valley of California makes the argument, in an opinion piece for the Modesto Bee, that if only the Delta restrictions could be dropped, allowing more surface water to be delivered to farms, they could stop overpumping the aquifers - resulting in subsidence, diminished water quality, and wholesale dewatering of their insurance supply.
Come on guys. Are we really supposed to be sympathetic to your plight? OK, you're behaving rationally under the circumstances because the State of California has chosen (start at p. 8) not to govern in the case of groundwater use, but you could still choose to manage the resource more wisely by setting up local governance that actually collects some data on groundwater use, sets some pumping limits, and tries to avoid some of the external costs of over-pumping. But no, this is just another lame opportunity to whine about the Delta smelt and how the little fish is harming farmers.
Time to move on.
Once again, thanks to Aquafornia for bringing this to my attention.
Monday, February 1, 2010
LA Board of Public Works calling for on-site rainwater retention
There has apparently been much talk of low-impact development (LID) standards in the Los Angeles area recently and now their public works board is calling for a new requirement that 100% of runoff from a 3/4 inch storm must be contained on-site on all new developments and some redevelopments. The plans are detailed in an LA Times article here.
Tucson has a rainwater harvesting ordinance that is aimed primarily at collecting rainwater to replace use of potable water for on-site landscape irrigation, but also has incidental effects of reducing off-drainage of stormwater. The LA proposal is strictly aimed at realization of benefits from reduced runoff.
In some respects, the LA proposal is much stricter than Tucson's ordinance because it requires containment of all water produced by a 3/4 inch rainstorm, while the Tucson ordinance requires using on-site generated rainwater for at least 50% of on-site landscaping irrigation. Tucson does have regulations about managing runoff generated by property development - and these have resulted in a few recent developments around town that manage stormwater on-site to avoid costly mitigation of runoff effects - but in most cases there is infrastructure in place to handle some or most runoff from developed property.
If LA successfully implements this change it could prove difficult to comply with. As the story notes, in some locations getting the runoff to infiltrate into the soil will be a real challenge. And a 3/4 inch rain might occur over 30 minutes or over 36 hours - with the amount of runoff generated varying greatly between the two. This definitely changes the type of development you do - how much of a lot is built on, use of underground parking (if storage of runoff is necessary) - it could get costly. As this is just a proposal at this point it will undoubtedly undergo some changes before implementation. But should be interesting to keep an eye on it.
h/t to Aquafornia for bringing the Times article to my attention.
Tucson has a rainwater harvesting ordinance that is aimed primarily at collecting rainwater to replace use of potable water for on-site landscape irrigation, but also has incidental effects of reducing off-drainage of stormwater. The LA proposal is strictly aimed at realization of benefits from reduced runoff.
In some respects, the LA proposal is much stricter than Tucson's ordinance because it requires containment of all water produced by a 3/4 inch rainstorm, while the Tucson ordinance requires using on-site generated rainwater for at least 50% of on-site landscaping irrigation. Tucson does have regulations about managing runoff generated by property development - and these have resulted in a few recent developments around town that manage stormwater on-site to avoid costly mitigation of runoff effects - but in most cases there is infrastructure in place to handle some or most runoff from developed property.
If LA successfully implements this change it could prove difficult to comply with. As the story notes, in some locations getting the runoff to infiltrate into the soil will be a real challenge. And a 3/4 inch rain might occur over 30 minutes or over 36 hours - with the amount of runoff generated varying greatly between the two. This definitely changes the type of development you do - how much of a lot is built on, use of underground parking (if storage of runoff is necessary) - it could get costly. As this is just a proposal at this point it will undoubtedly undergo some changes before implementation. But should be interesting to keep an eye on it.
h/t to Aquafornia for bringing the Times article to my attention.
Thursday, January 7, 2010
Some recent news from the Arizona water community
There were a few news items of note this week that I wanted to post on briefly.
First the good news. Kathy Jacobs of the University of Arizona (and formerly head of the Arizona Water Institute) was recently appointed to a new position in the White House (the one in Washington, D.C.) Office of Science and Technology Policy where she will work on climate change policy. Prof. Jacobs has pretty impressive credentials in that area and should be a real asset to the administration. Congratulations professor!
Second, the bad news. The latest issue of Southwest Hydrology showed up in my mailbox this week with a banner on the front indicating that it would be the last issue. This is a significant loss to the regional water resources community because SW Hydro has been a tremendous resource for disseminating new research and policy ideas in the management of water resources in arid and semi-arid hydrology. And they've been important to me because I have published a couple of short articles in the "On the Ground" section of the magazine. Betsy Woodhouse, who was the publisher has taken a new position at the University of Arizona and her colleague Gary Woodard gives the impression that they would like to bring the magazine back in the future if they can find a new funding source. But, their major source of funding - the National Science Foundation - has dried up for now. If anyone has ideas for keeping the magazine running send them to Gary Woodard (gwoodard@sahra.arizona.edu).
Finally, the final Phase II report on the Water & Wastewater Infrastructure, Supply and Planning Study (aka the Tucson/Pima County Water Study) has been released and can be downloaded from the study website - www.tucsonpimawaterstudy.com - of you're interested. The report will be formally presented to the local elected leaders of both jurisdictions in a special joint meeting next Tues., Jan. 12, at 9:00 am in the Pima County Administration Building, 130 W. Congress, 1st Floor, Board of Supervisors Hearing Room. Hope to see you there. If not, take a look at the report. It's no masterpiece but it provides a pretty good roadmap to a sustainable water future for this piece of dirt.
First the good news. Kathy Jacobs of the University of Arizona (and formerly head of the Arizona Water Institute) was recently appointed to a new position in the White House (the one in Washington, D.C.) Office of Science and Technology Policy where she will work on climate change policy. Prof. Jacobs has pretty impressive credentials in that area and should be a real asset to the administration. Congratulations professor!
Second, the bad news. The latest issue of Southwest Hydrology showed up in my mailbox this week with a banner on the front indicating that it would be the last issue. This is a significant loss to the regional water resources community because SW Hydro has been a tremendous resource for disseminating new research and policy ideas in the management of water resources in arid and semi-arid hydrology. And they've been important to me because I have published a couple of short articles in the "On the Ground" section of the magazine. Betsy Woodhouse, who was the publisher has taken a new position at the University of Arizona and her colleague Gary Woodard gives the impression that they would like to bring the magazine back in the future if they can find a new funding source. But, their major source of funding - the National Science Foundation - has dried up for now. If anyone has ideas for keeping the magazine running send them to Gary Woodard (gwoodard@sahra.arizona.edu).
Finally, the final Phase II report on the Water & Wastewater Infrastructure, Supply and Planning Study (aka the Tucson/Pima County Water Study) has been released and can be downloaded from the study website - www.tucsonpimawaterstudy.com - of you're interested. The report will be formally presented to the local elected leaders of both jurisdictions in a special joint meeting next Tues., Jan. 12, at 9:00 am in the Pima County Administration Building, 130 W. Congress, 1st Floor, Board of Supervisors Hearing Room. Hope to see you there. If not, take a look at the report. It's no masterpiece but it provides a pretty good roadmap to a sustainable water future for this piece of dirt.
Monday, December 21, 2009
Holiday Greeting
Happy holidays to my readers, followers, and fellow bloggers. Hope you have safe travels, good company, and a prosperous new year. I'll be back in 2010.
Chris
Saturday, December 12, 2009
The Technical Feasibilty of Rainwater Harvesting for Domestic Water Supply
Getting back (finally) to my most recent topic I have some numbers to throw out, in order to assess whether relying on rainwater for a domestic water supply is technically feasibly in a semi-arid or arid climate. Tucson would be considered semi-arid because our average rainfall is roughly 12 inches per year (although this year we have only had about 6-7 inches, which makes us arid at this time), but we are classified as arid because of our high evapotranspiration rate.
There are many skeptics who say that rainwater cannot be relied on as a water source in places like this because rain is too unreliable. Our annual rainfall typically comes in two seasons - winter and summer. Our winter rains tend to be gentle, slow rains that might occur several times a month, amounting to about 5 inches on average during the period December to April. Our summer rains, on the other hand, are known as monsoon rains because they result from a seasonal wind shift in summer, and often come in torrents. We typically receive between 5 and 7 inches of rain in the summer and it's not uncommon for the bulk of that rain to arrive in 3 or 4 rainfall events during the months of July and August. In between those seasons we might typically go for 2 or 3 months with little or no rain.
With that type of rainfall pattern, obviously, the key elements of rainwater harvesting will be capture area and storage. If you have a sufficiently large surface area from which to capture water and sufficiently large storage to hold onto that water during long dry periods rainwater becomes a feasible water supply.
Here are a few basic calculations of available water:
10" of rain falling on 2000 sq. ft. of roof surface will yield roughly 12,500 gallons of water.
10" of rain falling on 3000 sq. ft. of roof surface will yield about 18,700 gallons of water.
12" of rain falling on 2000 sq. ft. of surface yields about 15,000 gallons, and
12" of rain falling on 3000 sq. ft. of surface yields about 22,400 gallons of water.
If you take those numbers and average them out over the course of the year you come up with a range between 34 and 61 gallons per day. Obviously you are not going to maintain a home, yard, and pool by collecting rainwater unless you have a very large surface from which to collect the water. But it's perfectly reasonable for two people to survive on 61 gallons of water per day for indoor uses such as cooking, cleaning, bathing, and drinking.
But how do you make rainwater suitable for drinking? That is the tricky part, some of which I will try to address in a post on the regulatory limitations on use of rainwater for water supply. But in a general sense, you must install a home water treatment system to make this water suitable for consumption. This ranges from selecting proper roofing material that won't leach chemicals into the water falling on it, to engineering the collection system so the first flush of water coming off the roof is bypassed (to limit the bird poop in your water supply), to a system of filters and treatment technologies that will ensure no harmful bacteria or other nasties in your water. This is the primary annual cost of this type of water supply - the energy and maintenance of the treatment system. Most of the other costs are upfront when the collection and storage are installed.
This site includes some helpful information on what is necessary for making rainwater suitable for potable uses.
Is this type of system suitable for the average homeowner? Clearly not. But there are people out there who are willing to invest the money, time, and effort to get off the grid, or off the pipes in this case, and whose lifestyle allows them to live on only the amount of water necessary for basic, indoor human needs, without all the extraneous uses of high-quality drinking water many of us find necessary for our quality of life.
More when I find the time, including the aforementioned regulatory analysis of rainwater harvesting.
There are many skeptics who say that rainwater cannot be relied on as a water source in places like this because rain is too unreliable. Our annual rainfall typically comes in two seasons - winter and summer. Our winter rains tend to be gentle, slow rains that might occur several times a month, amounting to about 5 inches on average during the period December to April. Our summer rains, on the other hand, are known as monsoon rains because they result from a seasonal wind shift in summer, and often come in torrents. We typically receive between 5 and 7 inches of rain in the summer and it's not uncommon for the bulk of that rain to arrive in 3 or 4 rainfall events during the months of July and August. In between those seasons we might typically go for 2 or 3 months with little or no rain.
With that type of rainfall pattern, obviously, the key elements of rainwater harvesting will be capture area and storage. If you have a sufficiently large surface area from which to capture water and sufficiently large storage to hold onto that water during long dry periods rainwater becomes a feasible water supply.
Here are a few basic calculations of available water:
10" of rain falling on 2000 sq. ft. of roof surface will yield roughly 12,500 gallons of water.
10" of rain falling on 3000 sq. ft. of roof surface will yield about 18,700 gallons of water.
12" of rain falling on 2000 sq. ft. of surface yields about 15,000 gallons, and
12" of rain falling on 3000 sq. ft. of surface yields about 22,400 gallons of water.
If you take those numbers and average them out over the course of the year you come up with a range between 34 and 61 gallons per day. Obviously you are not going to maintain a home, yard, and pool by collecting rainwater unless you have a very large surface from which to collect the water. But it's perfectly reasonable for two people to survive on 61 gallons of water per day for indoor uses such as cooking, cleaning, bathing, and drinking.
But how do you make rainwater suitable for drinking? That is the tricky part, some of which I will try to address in a post on the regulatory limitations on use of rainwater for water supply. But in a general sense, you must install a home water treatment system to make this water suitable for consumption. This ranges from selecting proper roofing material that won't leach chemicals into the water falling on it, to engineering the collection system so the first flush of water coming off the roof is bypassed (to limit the bird poop in your water supply), to a system of filters and treatment technologies that will ensure no harmful bacteria or other nasties in your water. This is the primary annual cost of this type of water supply - the energy and maintenance of the treatment system. Most of the other costs are upfront when the collection and storage are installed.
This site includes some helpful information on what is necessary for making rainwater suitable for potable uses.
Is this type of system suitable for the average homeowner? Clearly not. But there are people out there who are willing to invest the money, time, and effort to get off the grid, or off the pipes in this case, and whose lifestyle allows them to live on only the amount of water necessary for basic, indoor human needs, without all the extraneous uses of high-quality drinking water many of us find necessary for our quality of life.
More when I find the time, including the aforementioned regulatory analysis of rainwater harvesting.
Sunday, November 29, 2009
Starting to think a lot about rainwater harvesting
Life has been extremely busy lately (even before holidays started rolling into the picture) and that has kept me from posting. But the ideas have been churning, just waiting for an opportunity to emerge onto these pages.
One thing I have been spending a lot of time thinking about and discussing with various people is the viability of rainwater harvesting for domestic water supply in places like Tucson. I know of people doing it so clearly it's possible. But I've been wondering what it would take to bring it more into the mainstream and maybe even be viable as a water source for a small development - not just the individual lot scale.
One person I know of who relies on such a system in the Tucson area is in a location where municipal water service is not available and drilling a private well is unreliable. So rainwater probably was their best option. They also weren't overly concerned with the cost of the system - they had resources to cover that and because of their desire to live in a remote location any option for water supply was going to be costly. I suspect this type of situation is the primary motivator for going with rainwater as a water source.
This makes me concerned that greater use of rainwater harvesting would lead to increased sprawl - as people move to locations where previously they may not have been able to build because of the lack of a water supply. But I think the reality is that the people who would choose this type of water supply are the ones who are likely to move into remote areas regardless and harvesting gives them an option for water supply that doesn't rely on a non-renewable source - such as groundwater (under most circumstances).
I'm still putting these ideas together and plan to post on this topic over the next few weeks, where I will try to outline the feasibility of rainwater as a domestic water source and the types of changes I think would be necessary (i.e. regulatory) to permit greater use of this type of system.
One thing I have been spending a lot of time thinking about and discussing with various people is the viability of rainwater harvesting for domestic water supply in places like Tucson. I know of people doing it so clearly it's possible. But I've been wondering what it would take to bring it more into the mainstream and maybe even be viable as a water source for a small development - not just the individual lot scale.
One person I know of who relies on such a system in the Tucson area is in a location where municipal water service is not available and drilling a private well is unreliable. So rainwater probably was their best option. They also weren't overly concerned with the cost of the system - they had resources to cover that and because of their desire to live in a remote location any option for water supply was going to be costly. I suspect this type of situation is the primary motivator for going with rainwater as a water source.
This makes me concerned that greater use of rainwater harvesting would lead to increased sprawl - as people move to locations where previously they may not have been able to build because of the lack of a water supply. But I think the reality is that the people who would choose this type of water supply are the ones who are likely to move into remote areas regardless and harvesting gives them an option for water supply that doesn't rely on a non-renewable source - such as groundwater (under most circumstances).
I'm still putting these ideas together and plan to post on this topic over the next few weeks, where I will try to outline the feasibility of rainwater as a domestic water source and the types of changes I think would be necessary (i.e. regulatory) to permit greater use of this type of system.
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