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Infiltration Trenches for Storm water and Water Supply? 2 for 1?

June 2, 2013
Climate, economy, Environment, groundwater, infiltration, infiltration gallery, infrastructure, innovation, management, riverbank filtrations, Tidal flooding, Uncategorized, water sewer management, water supplies
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The concept of horizontal wells arises from riverbank filtration concepts.  Riverbank filtration has been practiced for nearly 200 year in Europe, where the concept was to remove debris form polluted waters by drawing through the banks of rivers.  Much of the concepts for groundwater flow are related to the filtration ability of water to move through a porous media.  The concept was to dig trenches along the river and draw water from the trenches as opposed to the polluted rivers.  The concept worked relatively well.  The result is an abundant, dependable supply of high-quality water with a constant temperature, low turbidity, and low levels of undesirable constituents such as viruses and bacteria. Riverbank filtration also provides an additional barrier to reduce precursors that might form disinfection byproducts during treatment.

Now let’s look at this from another perspective, and we’ll pick on southeast Florida as is provides a great case study.  Sea level rise will inundate coastal property, both via coastal flooding and from a rise in groundwater. Since most stormwater drainage depends on gravity flow, drainage capacity will suffer as sea level rises reducing the head differential between interior surface waters and tide. Saltwater intrusion will be exacerbated. Furthermore, reduced soil storage capacity, groundwater flow and stormwater drainage capacity will contribute to increased flooding during heavy rain events in low-lying areas.  In low lying areas, current practices like exfiltration trenches will become impractical, as will dry retention will become wet retention.

Stormwater utilities will be faced with dramatic, currently unanticipated increases in capital expenditures and operating costs, and time will be needed for planning, design, securing permits and compliance. Additional local pumping stations on secondary canals will be needed to supplant the storm drainage system in order to prevent unacceptable ponding. Design capacities of these stations will depend on local rain patterns, drainage basin size and secondary canal system design.  Many will operate continuously, which means ongoing operations will increase substantially. Hundreds of pumping stations may be needed in some communities.

Permits will be a major challenge due to contaminants in the runoff as regulated by MS 4 Stormwater permits, and the inability to treat this water under the current structure. The cost and energy required for stormwater treatment would be a major concern going forward. But what if we sent this continuous flow to water plants as raw water?  All of a sudden we have a solution to two problems – stormwater and raw water supplies.  How often do you see a 2 for 1 solution?

Does Delaying Decisions on Infrastructure Help Us?

May 21, 2013
Development loans, economy, Environment, funding, infrastructure, innovation, Insurance, Leadership, management, sea level rise, stormwater, sustainability, Tidal flooding, Uncategorized
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If you live on an island, and your groundwater table is tidal, what should your datum be for storm water planning purposes?  Average tide?  High tide?  Seasonal high tide?  If you are the local official with this problem, what do you do, realizing that the difference from mean tide and seasonal high tide (when most flooding occurs) is 1.5 feet?  Realizing that property and infrastructure is at much higher risk for periodic inundation, does the failure to address the problem indicate a lack of willingness, understanding, hope or leadership?  We see all four responses among local officials, but the “head in the sand” mode is the most curious.  It’s tough challenges that often define leaders.  With sea level rise, there is time to plan, construct infrastructure in stages, arrange funding, and lengthen the life of infrastructure and property.  Meanwhile, those insurers, banks and the public we talked about in a prior blog wait and watch.

Talk Radio discussion

May 18, 2013
Climate, communciations, economy, Environment, funding, groundwater, infiltration, infiltration gallery, infrastructure, innovation, Leadership, management, sea level rise, stormwater, sustainability, Tidal flooding, Uncategorized
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Talk Radio discussion

Hi All.

This is a radio show I did this week.  One of 4 I have scheduled.  It talks about me and my company, outlook, thoughts.  Take a listen.  Let me know what you think!

Fred

Planning for Change (like sea level rise)

May 1, 2013
Banking industry, Climate, Development loans, Environment, groundwater, infrastructure, Insurance, Leadership, planning, sanitary sewer, sea level rise, stormwater, sustainability, Uncategorized
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After my last post, I was asked about sea level rise and how to get started with the issue in a very “red” area as it was characterized.  I have come to the conclusion that the insurance industry will make sea level rise real for politicians in those places where it is impermissible for bureaucrats to discuss it.  Here’s why.  Say you have a house in a low lying area that is vulnerable to sea level rise and/or storm surge.  One is permanent, the other temporal, but in both cases are potentially catastrophic if you live in this house.  You bought the house, got a loan for 80 or 90% of its value and then got insurance for it.  Now the insurance is there to insure that if your house gets swept away or damaged, there will be enough money to pay off your loan.  That’ s what many people miss.  Insurance is for the bank, no you, which is why your loan documents require that you get and hold insurance while you have the house.  After your loan is paid off, there is no such requirement.

Now let’s say we are out 20 years.   You have enjoyed your house but have decided to sell it.  Now the banks will value it and are willing to loan say 80% of its value.  They of course assume that the house will increase in value with time so even if you make no improvements, if they have to foreclose on it they will get their money back (a major part of the problem with the financial crisis of 2008 was they banks could not get their money out of the properties).   Even if it doesn’t, as your loan is paid down, their risk decreases.   The loan documents require that you get insurance to cover your costs.

So far so good, but what happens when the insurers will not give you insurance for the full value of the property?  In Florida the State creates Citizen’s to deal with the fact that private, commercial insurers saw too much risk in coastal areas and refused to issue policies.  Now the State and Citizen’s have the risk.  Fine, but that isn’t dealing with the same issue – if the insurer think the value of the property will decrease, or the risk increases a lot, they will not issue policies. Or they will revise policies to say they will pay once – but will not insure you for rebuilding.  You may think this will not happen, but Citizen’s is already discussing this option.  Hence if you lose your house, they will pay you (so you can pay the bank, and then you are on your own.  Now the bank may be willing to offer you a distressed property as an options (Welcome to Detroit), but that won’t be in the same risk zone.

Take this further, let’s say Citizen’s for example says we will pay full value if you lose the house but will not insure a rebuild?  That means they probably will not give insurance to the guy who wants to buy our house in 20 years.  How much is your house worth now?  Probably nothing, which means now the bank will be looking at your insurance coverage and say – whoa – if the house is not worth anything on a resale, that means they may not get paid when you sell your house if you sell if before it is paid off (the norm)!!  That is an unacceptable risk, and they need a solution.  Of course if your house suddenly has no value, it means local governments get no revenue for taxes (good for you, but bad for providing essential services like storm water.  You may not believe this discussion is happening, but it is.

So here’s what I think happens.  I think the banks figure this out and start looking at vulnerability as a part of loans.  I think they start thinking about what the value in 20 or 30 years might be and if they can get their loan monies back out of property.  That will slow property values.  I think the insurance industry does the same, and working with banks will further set the prices acceptable for vulnerable property.  They are not good investments. If you own such property, you may get insurance in the short-term, but long-term your house value may decrease.  At some point, your house will have no resale value, unless……

BUT there iis a big caveat to all this.  Coastal areas are high value markets.  Lots of activity and lots of investment opportunities.  It all depends on what is being done to protect those properties, and depending on the federal governments to bail out private property is unrealistic.  It is a local issues, so I also think the banks and insurance industry will start looking at what local governments are doing to protect investments in private property.  Do they have a sea level rise adaptation plan?  Are the storm water systems updated/upgrades/maintained?  Are roads, water supplies and sewer systems capable of functioning under the changed condition?   Is there a 50 or 100 year vision on how the community adapt to nature?  If yes, there is comfort that investments are protected.  If everyone’s head is buried in denial…..Detroit’s calling.  U-haul anyone?

PS  No disrespect to Detroit, my father’s hometown and the home to many of my current and departed family.  For those who do not know, Detroit is high, has access to lots of water, sewer, roads, power and lots of land at reasonable cost, along with a jobs and manufacturing history.  Perfect opportunity, one not lost on our ancestors.

How Long should the Leadership vision be?

April 29, 2013
Climate, Environment, finance, groundwater, infrastructure, Leadership, management, planning, sustainability, Uncategorized, water sewer management, water supplies
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We do 5, 10 and 20 year plans for infrastructure.  But how long do we expect to this infrastructure to last?  For example, how many roads only last 10 or 20 years?  Most roads only seem to grow with time.  Ancient Roman roads are the basis for many current roads.  We keep adding roads – few are ever abandoned. They simply do not go away.   So a 5, 10 or 20 year planning period makes little sense.

Roads are not the only limit.  The WPA-era water mains are approaching 80 years old, and still providing good service, and our Clean Water Act-era sewer improvements are approaching 40.  Sewer lines are similarly situated.  Many water plants are over 70; we celebrate 100 years on many.  Again, planning for only 20 years makes little sense in the context of the larger length of time.

More interesting, we rarely borrow money to pay for these projects for less than 20, 30 or 40 years.  So our infrastructure outlives our plans and our borrowing.  Often permits are less that the borrowing for infrastructure, which can cause stranded capacity in plants that may never be used.  Miami-Dade County has such a situation – they are not alone.

Let’s look at this in the context of groundwater withdrawals.  There are areas across the US where groundwater levels have fallen. They have fallen because of human activity to pump them for crops and water use.  Colorado has a 100 year management plan in the Denver basin which is basically make the water last 100 years.  Then what?  Texas has shorter plans.  The eastern Carolina drained parts of the Black Creek already, so this is not a theoretical western state issue only.  How do we address this?

Or let’s go back to Miami-Dade County the outer banks of North Carolina, historical downtown Charleston, SC, and many other venues where sea level rise could impact water, sewer, storm water and roadway infrastructure. As we redevelop those area, should plans look at the true life of those assets (100 years) vs. the 20 year plan?

Both issues involve the sustainability of infrastructure systems, which means the ability to adapt them to changing future conditions.  We have known for 10-15 years that stationarity is no longer accepted for future projections.  But we need leadership to move the infrastructure planning to the future changing conditions.

Barriers to Public Sector Leaders? Part 2

April 5, 2013
Environment, infrastructure, innovation, Leadership, management, planning, sustainability, Uncategorized, water sewer management
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In the last blog we discussed the three issues were associated with risk tolerance in the public sector which stifles innovation, application of business principles to public sector efforts, and the lack of vision and understanding of consequences.  In this blog we will explore the second issue – application of business issue into the public sector.  The public and private sectors are different.  We need to recognize this.  For the most part, the public sector does those things that the private sector deems to be averse toward profits.  Clearly everyone needs water, but if you can’t get people to pay for it, you can’t make a business out of it.  Enter government, which has the ability to lein and condemn houses for failure to be connected.  A bit more incentive.

Or take fire service.  Fire service in New York was once a private affair.  You paid and the fire company would respond.  If your house caught fire and you had not paid, then what.  No one shows.  This was illustrated nicely in the movie “Gangs of New York” and was the catalyst for creating the NYC fire department.  And many others.  It simply is not acceptable to have some people but not all, because of the risk to everyone.  Vaccinations are the same way.  Much easier to implement by government.  And historically this is what has happened.

But we often hear the commentary about how we should be “running government like a business.” However I suggest this is an oversimplified argument that ignores true differences in the objectives of the public and private sector.   The two sectors are different and let’s look at an example.  If you were in charge of Ford Motor Company and let’s say you had only two vehicles, the F150 pickup (largest selling vehicle in the US) which has a high profit margin, or a passenger vehicle which does not have a high profit margin and does not sell nearly as well.  If you determine that your revenues are likely to decrease as a result of the economy, where do you make cuts?  There is an easy metric – cutting costs and reducing production of the passenger vehicle might actually maintain or improve your profit margin.  So that manager looks like a brilliant leader.

He (generic) now gets hired to run a City because of his success at Ford.  The City of course has a revenue shortfall, so what does he do? Much more difficult.  He has police, fire, parks and recreation, planning, etc. so where do you cut.  None of them are profit centers; they are all services, the value of which cannot easily be measured.  He could evaluate the risk of higher losses if he cuts the fire department, but that likely has other issues.  Hence there is a distinct different in the metrics between the sectors.  So he cuts all services the same amount – sharing the pain because there is no means to measure the impact of success of cutting costs. Every government employee recognizes this method to reduce the budget.  So how would that have worked at Ford?  Well, cutting back on the F150 and the passenger vehicle the same percent would likely make the overall situation worse, not better.  A Ford executive making that type of decision would be roundly criticized and likely dismissed, but that same person is viewed as a successful manager in the public sector.  Nonesense.  He’s still an idiot and deserves to be fired.  Ditto the other officials that go along with such simplistic decision-making.

The public and private sectors are different, and while there are commonalities, the inability to directly measure impacts on the public sector make private sector applications suspect in many situations.  Curtaining services that have much larger, unanticipated consequences, a risk that dissuades innovation because of the inherent risks and the risk of impacting some powerful constituency. Simplistic solutions that are commonly offered up simply mean that these “leaders” simply do not understand what their “products” are nor which ones are a priority.  And hence they abdicate their decision-making for simplistic solutions that seem “fair.”  Successful leaders in business and government will tell you lesson #1 is life is not fair. We need leadership to help us make better decisions.

Should Coastal Utility Master Plans Include Sea Level Rise?

March 21, 2013
Climate, communciations, Environment, finance, funding, infiltration gallery, infrastructure, innovation, Insurance, Leadership, management, planning, riverbank filtrations, sea level rise, stormwater, sustainability, Uncategorized, water sewer management, water supplies
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Planning is a process utilized by utilities in order to reach a vision of the utility as defined by the customers or the governing board, or to meet certain demands for service projected to be required in the future.  Understanding and managing the utility’s assets provides important information related to the ongoing future direction of the utility system.  However, the only method to develop that future direction is through the planning process.  Planning should be undertaken on a regular basis by all enterprises in an effort to anticipate in to anticipate needs, clarify organizational goals, provide direction for the organization to pursue and to communicate each of these to the public.  With water and wastewater utility systems, it is imperative to have ongoing planning activities, as many necessary improvements and programs take months or years to implement and/or complete.  Without a short and long-term plan to accomplish future needs, the utility will suffer errors in direction, build unnecessary or inadequate infrastructure and pursue programs that later are found to provide the wrong information, level of service or type of treatment.

Planning can provide for a number of long-term benefits – improvements in ISO ratings to lower fire insurance rates, renewal of improvements as monies become available, rate stability and most importantly – a “vision” for the utility.  In creating any plan for a utility system, efforts to understand the operating environment in which the utility operates must be undertaken.  Second, the needs of the utility must be defined – generally from growth projections and analyses of current infrastructure condition from repair records or specific investigations.  By funneling this information into the planning process, the result of the effort should be a set of clear goals and objectives needs to be defined (Figure 8.1).  However, the types of goals and objectives may vary depending on the type of plan developed.  There are 4 types of plans that may result from the planning process.

  • Strategic Plans – action oriented for management level decision-making and direction
  • Integrated Resource Plans – Actions for utility management to tie all parts of the system together
  • Facilities Plans – for SRF loans support
  • Master Plans – to support capital improvement programs

Any utility planning effort should start with a description (and understanding) of the local environment (built and otherwise).  An understanding of the environment from which water is drawn or to be discharged is important.  Both water quality and available quantity, whether surface or ground water, are profoundly affected by demand.  A reduced demand for surface water helps prevent degradation of the quality of the resource in times of low precipitation.  Reduction in the pumping of ground water improves the aquifer’s ability to withstand salt water infiltration, potential surface contamination, upconing of poorer quality water, contamination by septic tank leachate, underground storage tank leakage, and leaching hazardous wastes and other pollutants from the surface.  Over-pumping ground water leads denuding the aquifer or to contamination of large sections of the aquifer.  Planning for is necessary for surface water systems.  Therefore, source water protection must be a part of any water planning efforts, including the appropriate application sites and treatment needs for reuse and residuals.

So let’s toss sea level rise into the mix.  What happens when sea level rise inundates coastal areas with saltwater and increase freshwater heads inland?  How do we fix that problem and should be plan for it.  Clearly master planning should include this threat (as applicable), just as any regulatory issue, water limitation, disposal limit or change in business practices should be considered.  One means to reduce the impact of sea level induced groundwater levels is infiltration galleries that may operate 24/7.  These systems are commonly used to dispose of storm water (french drains or exfiltration trenches) but what happens if the flow is reversed?  Water will flow easily into the system, just as it does for riverbank filtration. The water must be disposed of, with limited options, but let’s toss a crazy idea out there – could it be your new water supply?  Just asking, but such a system would not be unprecedented worldwide, only in the coastal communities of the US.

When do we get serious about sea level rise?

March 18, 2013
Banking industry, Climate, Development loans, Environment, finance, groundwater, infrastructure, Insurance, Leadership, management, planning, sanitary sewer, sea level rise, stormwater, sustainability, Tidal flooding, Uncategorized, water sewer management, water supplies
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Based on my last blog, his inquiry came to me.  And I think I actually have an answer:  when bakers and insurance companies decide there is real exposure.  Let’s see why it will take these agencies.  There is very little chance, regardless of good faith efforts, significant expertise, or conscientious bureaucrats to stop growth and development.  The lobby is simply too strong and local officials are looking for ways to raise more revenues.  Development is the easiest way to increase your tax base.  As long as there are no limits placed on develop-ability of properties (and I don’t mean like zoning or concurrency), development will continue.  But let’s see how this plays out.  Say you are in an area that is likely to have the street inundated permanently with water as a result of sea level rise (it could be inland groundwater, not just coastal saltwater).  For a time public works infrastructure can deal with the problem, but ultimately the roadways will not be able to be cleared.  Or say you are located on the coast, and repeated storm events have damaged property.  In both cases the insurance companies will do one of three things:  Refuse to insure the property, insure the property (existing) only for replacement value (i.e. you get the value to replace) but no ability to get replacement insurance, or the premiums will be ridiculous.  We partially have this issue in Florida right now.  Citizen’s is the major insurer.  It’s an insurance pool created by the state to deal with the fact that along the coast, you cannot get commercial insurance.  So Citizens steps in.  The state has limited premiums, and while able to meet its obligations, in a catastrophic storm would be underfunded (of course in theory is should have paid out very little since 2006 since no major hurricanes have hit the state, but that’s another story). 

As the risk increases, Citizens and FEMA, the federal insurer, have a decision to make.  Rebuilding where repeated impacts are likely to happen is a poor use of resources and unlikely to continue.  Beaches and barrier islands will be altered as a result.  The need will be to move people out of these areas, so the option above that will be selected will be to pay to replace (move inland or somewhere else).  Then the banks will sit up.  The banks will see that the value of these properties will not increase.  In fact they will decline almost immediately if the insurance agencies say we pay only to relocate.  That means that if the borrowers refuse to pay, the bank may not be able to get its money out of the deal on a resale.  We have seen the impact on banks from the loss of property values as a result of bad loans.  We are unlikely to see banks engage in similar risks in the future and unlikely to see the federal insurers (Fannie Mae, Freddie Mac) or commercial re-insurers like AIG be willing to underwrite these risks.   So where insurance is restricted, borrowing will be limited and borrowing time reduced.  That will have a drastic impact on development.  The question is what local officials will do about it?

There are options to adapt to sea level rise, and both banking and insurance industries will be paying close attention in future years.  Local agencies will need a sea level rise adaptation plan, including policies restricting development, a plan to adapt to changing sea and ground water levels including pumping systems to create soil storage capacity, moving water and sewer systems, abandoning roadways, and the like, and hardening vulnerable treatment plants.  Few local agencies have these plans in place.  Many local officials along the Gulf states refuse to acknowledge the risk.  What does that say about their prospects?  Those who plan ahead will benefit.  Southeast Florid a is one of those regions that is planning, but it is slow process and we are only in the early stages.

Groundwater Accelerates Sea Level Rise

March 14, 2013
Climate, communciations, Development loans, Environment, funding, groundwater, infrastructure, Insurance, Leadership, management, planning, sea level rise, stormwater, sustainability, Tidal flooding, Uncategorized
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Regardless of the causes, southeast Florida, with a population of 5.6 million (one-third of the State’s population), is among the most vulnerable areas in the world for climate change due its coastal proximity and low elevation (OECD, 2008; Murley et al. 2008), so assessing sea level rise (SLR) scenarios is needed to accurately project vulnerable infrastructure (Heimlich and Bloetscher, 2011). We know that sea level has been rising for over 100 years in Florida (Bloetscher, 2010, 2011; IPCC, 2007). Various studies (Bindoff et al., 2007; Domingues et al., 2008; Edwards, 2007; Gregory, 2008; Vermeer and Rahmstorf, 2009; Jevrejeva, Moore and Grinsted, 2010; Heimlich, et al. 2009) indicate large uncertainty in projections of sea level rise by 2100. Gregory et al. (2012) note the last two decades, the global rate of SLR has been larger than the 20th-century time-mean, and Church et al. (2011) suggested further that the cause was increased rates of thermal expansion, glacier mass loss, and ice discharge from both ice-sheets. Gregory et al. (2012) suggested that there may also be increasing contributions to global SLR from the effects of groundwater depletion, reservoir impoundment and loss of storage capacity in surface waters due to siltation. The loss of groundwater, mainly from confined aquifers, is troubling, and currently completely unknown. The contribution of carbon dioxide, commonly occurring in deep groundwater is also unknown. To gauge the risk to property in southeast Florida, Southeast Florida Regional Climate Compact and Florida Atlantic University reviewed twelve different projections of SLR and its timing. The consensus was 3” to 7” by 2030 and 9” to 24” by 2060. From the literature review and analysis, it was concluded that approximately 3 ft. of sea level rise by 2100 would a suitable scenario and time frame to illustrate the methodology presented in this article. To allow flexibility in the analysis due to the range of increases within the different time periods, an approach that uses incremental increases of 1, 2, and 3 feet of SLR was considered for risk scenarios. An issue normally ignored in sea level rise projections is groundwater. The importance of the groundwater table in the model is that it is responsible for determining the soil storage capacity. Soil is composed of solids, water, and air (voids). Soil storage capacity depends on physical and chemical properties, water content of the soil, and depth to the water table or confining unit (Gregory et al 1999). As the rain infiltrates the soil, unsaturated pores quickly fill up, effectively raising the water table (Gregory et al 1999). For example efforts, a groundwater surface elevation map was derived based well site information available from the USGS (http://groundwaterwatch.usgs.gov) that had a minimum of 35 years of continuous data. Using GIS, an inundation model was created in GIS by subtracting the groundwater surface model from the digital elevation model with the difference in elevation being the soil storage capacity. The photo shows the evolution of these features as applied to a section of northwestern Miami-Dade County. What this indicates it that the impact of sea level rise on low-lying inland areas may be far different that the projections using the bathtub models. It also means that wellfields, sewer mains, roadways and storm water systems will be affected far more quickly than projected from bathtub models. The method used here suggested that the estimated may be off by a factor of two of three.

Optimizing Water Supplies in the Face of Climate, Economic and Population Demands

February 26, 2013
Climate, Environment, infrastructure, Leadership, management, power demands, power-water nexus, sustainability, Uncategorized, water supplies
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The world population is expected to grow to over 9 billion by 2050, an exponential trend that has continued for several hundred years and see no end it site.  Megaregions as people flock to cities and industry will be commonplace.  The question is how will water supplies be impacted, or impact this trend.  Interestingly it varies everywhere.  For example, China and India are not expected to reap major benefits from climate changes, so their economies will grow as will populations.  They continue to construct coal fired power plants, and impact carbon dioxide and pollution levels, which does not help the climate issues.   Recall that Beijing was basically shut down for several days recent due to smog – seems like I recall the first air pollution regulations stemming from Henry the VIII decision to move the coal plants out of London during his reign 500 years ago because of pollution, but perhaps we need to relearn history J.  Of course China and India are expected to be less affected than the more historically developed countries in the northern latitudes that have been moving to renewable and less impactful power solutions with good reason.  Aside from these two economies, the rest of the northern latitudes are likely to see changes in temperature, variation in precipitation patterns and drought frequency changes.  That has major impacts for a billion people who will see water supply shortages occur much more often, and create a whole host of “winners” and “losers” in the water supply category.  Conflicts may result from the need to change increase water supplies as desperation kicks in.  Lawrence Smith, in his book 2050, suggests that while the far northern countries, the US, Russia, the Scandanavian countries, and Canada may see more land for agriculture and more water (at least in some areas), those warmer countries in the sub-Sahara, will become more desperate and dangerous to the world order.  Water will be the new oil, and the tipping point for sustainability, akin to peak oil, needs to be developed.  The cost will be significant, but the failure will be catastrophic to global economies.  This is part of why the global pursuit of renewable power, local solutions and green jobs.  It is why the definition of sustainable water supplies continues to evolve as we understand that the impacts, or the constraints of water supplies is far more reaching than most engineers and planners have traditionally dealt with.  AWWA published a Sustainable Water CD several years ago.  It was a series of papers of different aspects of sustainability as applied to water resources.  The last paper summarized the findings and compared it to the initial paper discussion.  The conclusion was the concept is evolving.  Climate, power, agriculture, natural systems, local economies, local economic contributions to regional and national economies and politics all impact pure science recommendations for water supply allocation.  The question is can we overcome the politics to create a optimized science solution to sustain water supplies and economies.  An old Native American proverb comes to mind:  We do not inherit the Earth from our grandparents, we borrow it from our grandchildren.