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Tag Archives: sea level rise

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.

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.

Sea Level Rise may Impact low lying areas faster than we think

February 23, 2013
Climate, communciations, Environment, groundwater, infrastructure, Leadership, Marketing water, planning, power demands, power-water nexus, sanitary sewer, sea level rise, stormwater, sustainability, Tidal flooding, Uncategorized, water sewer management
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One of the major issues involved with climate changes is sea level rise. Florida has experienced 9 inches of sea level rise since 1900. Projections are 2-3 feet by 2100, perhaps more. Modeling done by my students and I at FAU has demonstrated that in low lying areas, sea level rise will also impact groundwater levels, and accelerate inland flooding. The graphs above compare the traditional bathtub model used by most investigators and our adjusted for groundwater level model. You wee added inland areas of flooding which complicated storm water flooding issues much faster than sea level rise might indicate.

Leadership Part 2

December 20, 2012
Climate, communciations, Environment, finance, funding, infrastructure, Leadership, management, Marketing water, planning, sea level rise, stormwater, sustainability, Uncategorized, water sewer management, water supplies
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Among the many things I do is work with college seniors as they get ready to graduate and hit the job market.  The changes you use in many of these students over that last year in school is often significant, and in some cases remarkable.  Different students grow differently and the potential starts to appear.  Some gain confidence in their skills and begin to grow into the profession.  Some of these students are likely to make good leaders in the field in the future.  But trying to guess which ones and why it is often a challenge.  However I want them all to have some concept of what leadership is all about.  For many of them, they will end up in the water/wastewater/stormwater field.  They are going to have to deal with tough issues like rebuilding deteriorating infrastructure, sea level rise, climate changes, stressed water supplies, energy demands and a more demanding electorate.  They will recommend increasing water and wastewater fees.  But will they have the skills to encourage decision-makers to move forward with the needs of the system.  You see, that’s where leadership comes into play.  Often it is little things that set things into motion.  Our engineers go into the world with a technical skills et, that ability to learn to solve problems with solutions.  We try to encourage them to be creative.  An assigned reading is “The Cult of the Mouse” by Henry Caroselli, who urges creativity above profits in the workplace.  Mr. Caroselli is right in that it is creativity that allows us to come up with innovative solutions, the ones that change how we live.  It is also where the patents and economic opportunities exist.  America rose to greatness in the 20th century in large part because of automobiles – we figured that out and it made some many things possible.  Computers became common place in the latter part of the century.  We use the technology for both in the water/wastewater/stormwater industry.  In fact they have made us so much more efficient that costs have not climbed as fast as they might have, which is why cable tv is normally more expensive than your water bill.  Which one do you need to live?  My hope is that today’s students figure out energy solutions that will carry us forward as a world leader in the 21st century.  Those alternative energy options, greater efficiency of current technology.  Each will allow the utility industry to improve it’s efficiency further.  The City of Dania Beach built the world’s first LEED Gold water plant.  That took a little vision on the part of the utility director Dominic Orlando.  And a cooperative team of consultants and students.  When we give these projects to young people we can be surprised because they often don’t know that “that’s not the way we do it.”  Well that’s exactly what Mr. Caroselli said.

So we look for leadership.  Creativity, innovation and the “Can-do” mentality are part of leadership, but not all.  There is that ability to set a vision, like Mr. Orlando did in Dania.  There is the ability to convince decision-makers of the wisdom of an idea, as opposed to doing like we always did to make the shareholder happy as Mr. Caroselli noted.   Selling innovation is often the hard part because that’s were the costs are.  But there is more.  Often the selling of a good idea is difficult.  You can be ridicules by the status quo.  Many ideas are just lost in the shuffle because they never receive a voice.

Leadership is often not understood at the time it is occurring.  Ok, maybe we figured this out when Lincoln was President, but if you read accounts of his Presidency, the early years are marked with indecision and backtracking before he got it right.  Most of that is forgotten in lieu of the ultimate results.  Many of the issues we face today need real leadership to create a long-term solution.  The “fiscal cliff” issue is a prime example, as it the long-term need for solutions for social security, Medicare and medical costs in general.  The need to fix the infrastructure that made our economy strong should be among those priorities also.  Remember, we don’t remember the councilman, mayor, legislator. manager, director or President who did not raise taxes or water bills.  They do remember those who solved problems

Planning or Just Shots in the dark…

October 31, 2012
Climate, communciations, Environment, infrastructure, Leadership, management, planning, sea level rise, sustainability, water sewer management, water supplies
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I had an interesting email exchange with a guy in north Florida who was trying to educate the Legislature on why planners are always wrong with their projections and their studies should be ignored as a result.  His specific issue was water supply, but it could have been any number of issues.  His argument was that the projections for water use made in 1976 were incorrect and in fact total water demands in the State had been basically flat over that period.  He’d be unhappy to know that Florida mimics the rest of the country.

Ok, I admit that in addition to being an engineer, I have a minor in planning and a degree in public administration.  I attempted to communicate with him about the purpose of planning, not that it helped.  Planners outline projections of what things will likely be IF not changes are made.  The reason is to prompt policy or behavioral changes prior to reaching critical tipping points.  The argument in 1976 was that Florida would run out of cheap water if current trends continued.  In the intervening years, there have been major efforts toward water conservation, low flow bathroom fixture and major changes to irrigation practices.  All of which made the water picture far better than the 1976 projection.  See the planners were not wrong – the projections indicated the problem if nothing was done, and acted in part as a catalyst for change.  This is what planners dealing with water supply needs, sea level rise and a host of other planning issues are supposed to do.  If we understand what the potential problems are, maybe we can take action to avoid tipping points.  This is not to say all projections are perfect or even correct, but the idea is to avoid reaching a point of no return.  Isn’t that what smart people should do?  Apparently not to the guy on the other end of the email.  Happy Halloween.  Er, no this was just scary because it was real!!

Sea Level Rise? Or Rising?

October 23, 2012
Astronomical tides, Climate, Environment, groundwater, infrastructure, Leadership, management, sea level rise, stormwater, sustainability, Tidal flooding, water sewer management, water supplies
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October is the month that brings us the astronomical tides, or locally to the coasts, the annual high, high tide.  The position of the moon relative the Earth creates a slight alteration in the gravitational pull of the moon on the oceans so high tide, is, well high!  If you lived in a coastal areas, what did you see?  Or experience?  Southeast Florida was rife with email chatter and photographs of flooded streets, yards, and canals.  The City of Fort Lauderdale sent notices to residents warning them about the tides.  We had no rain, just the tide coming in.  These are low lying areas that 20 years ago did not flood except during storms.  This is just a phenomenon that has been monitored in coastal areas over the past 5-10 years, depending on the complaints that have come into local officials.

One of the more interesting complaints I received in my career was in Hollywood Florida where a resident complained about the “fish in the street.”  Sure enough, the storm drain in front of his house was connected directly to the Intracoastal waterway and the October tides had pushed the saltwater up through the catch basin into the street.  Now these weren’t snook or redfish, they were little fish escaping the snook and redfish, about 3-5 inches long.  Pretty funny stuff if you think about it.  Realizing the problem, I called him 3 hours later and asked if the problem had been solved.  He said told me I was a genius to fix that so fast.  My boss told me to take advantage of luck and drop the explanation, but to design a solution (which we did).  My boss was right, but the call made me more cognizant of the issue.

15 years later, I have a student developing models of what happens during the annual high and average tides, especially with respect to the potential for flooding in low lying areas where groundwater is just below the surface.  His work is impressive.  A lot more land, especially inland, may flood as a result of the annual tides, which are a precursor to the long term trend of rising seas.  See the groundwater has a slight upward gradient as you move inland.  As a result, you cannot use the tide levels to predict inland flooding, you need to add the tides on top of historical groundwater levels.  Of course the wet season is the summer in Florida, so the October tides come just at the time groundwater levels are highest.  But at least we can determine where the stormwater pumping improvements need to go.

Determining where stormwater pumping is needed is only part of the problem.  As sea levels rise, more stormwater management will be needed and a place to put the water will become a problem.  Discharging nutrient laden stormwater to tide is not a good answer when you have fragile reefs offshore.  NOAA’s Florida Area Coastal Environment  (FACE) Initiative outline this (see intensives study – http://www.aoml.noaa.gov/themes/CoastalRegional/projects/FACE/Publications.htm).  Instead, perhaps at some point we may develop infiltration systems to capture this high water table “problem” and convert it to water supplies, solving two issues for southeast Florida.  Might be 2030, but we probably should be doing some planning….