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The Costs of SLR and Rainfall

August 23, 2016
asset management, engineering, finance, florida, Holistic Water Planning, infrastructure, Leadership, local government, management, Risk, Risk Management, sea level rise, stormwater, surface waters, sustainability, utilities, Water Funding, water sewer management
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The reliability of the assets within the area of interest starts with the design process in the asset management plan. Decision-making dictates how the assets will be maintained and effective means to assure the maximum return on investments. Through condition assessment, the probability of failure can be estimated. Assets can also fail due to a growing area that may contribute to exceeding its maximum capacity. Operation and maintenance of the assets are important in reassuring a longer life span as well as getting the most out of the money to be spent. Prioritizing the assets by a defined system will allow for the community to see what areas are most susceptible to vulnerability/failure, which assets need the most attention due to their condition, and where the critical assets are located in relation to major public areas (hospitals, schools, etc.) with a high population.

So what happens when conditions change?  Let’s say sea levels are rising and your land is low.  What would the potential costs be to address this?  Better yet, what happens if it rains? We looked at one south Florida community and the flood stage for each based on 3 storm events: the 1:10 used by FDOT (Assumes 2.75 inches in 24 hours), the Florida Building Code event that includes a 5 in in one hour event (7 in in 24 hrs), and the 3 day 25 year event (9.5-11 inches).

Of no surprise is that the flooding increases as rainfall increases.  Subsequent runs assumed revisions based on sea level rise. The current condition, 1, 2 and 3 ft sea level rise scenarios were run at the 99 percentile groundwater and tidal dates and levels.  Tables 2-5 depict the flood stage results for each scenarios.  The final task was designed to involve the development of scenarios whereby a toolbox options are utilized to address flooding in the community.  Scenarios were to be developed to identify vulnerabilities and cost effectiveness as discussed previously.

The modeling results were then evaluated based of the accompanying infrastructure that is typically associated with same.  A summary of the timelines and expected risk reductions were noted in the tables associated with storm and SLR scenarios.  This task was to create the costs for the recommended improvements and a schedule for upgrading infrastructure will be developed in conjunction with staff.  Two issues arise.  First, the community needs to define which event they are planning to address and the timelines as the costs vary form an initial need of $30 million to over $300 million long-term.  Figure 1 shows how these costs rise with respect to time.  The long-term needs of $5 million per 100 acres matches with a prior effort in Palm Beach County.

SLR costs

Figure 1  Summary of Costs over the 3 ft of potential sea level Rise by 2011, under the 3 storm planning concepts.

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1/4 the semester is Gone!

September 15, 2014
Climate, communciations, debt funding, Detroit, Economic Bubbles, economy, finance, growth, infrastructure, JObs, Leadership, management, planning, politics, Risk, Uncategorized, Water Funding
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The first month of the fall semester has slammed me, which accounts for a little less blog activity on my part.  But as fall rolls in many local governments are dealing with final budgets, new projects and dealing with taxes and fees.  Students are back to school and industries are looking to the end of the year and 2015.  How fast time flies.  Our students that graduated last spring all have jobs and half of our seniors that will graduate in December do as well.  With engineers or contractors.

The good news is that the economy continues to tick up, construction and construction jobs are back to 2005 levels (which if you recall was a lot), and the stock markets are making money for somebody because they are up as well.  Alan Greenspan can complain that housing maybe lagging, but that is more a lack of people having funds or being able to move.  Meanwhile construction of projects that were deferred might be addressed?  Time will tell but it raises an interesting question –  can we plan on growth forever?  We assume a continuous growth rate (like 1 or 2% per year), but is that reasonable since it means more people come to an area each year than they did the year before?  Works for bacteria, maybe not so much for people.  Ask Detroit.  Or Cleveland.  And does this type of growth create unintended consequences for us?  I think this is a  good question for a future blog and of course a question that economists and politicians do not want to answer.  It would be highly disruptive to our plans.   So since it is election season again, we all need to be prepared for the inundation of campaign sales pitches that try to convince us to vote for someone, or more likely to vote against someone.  That’s probably not the way it was intended to go, but it’s what politics has degenerated to in so many places.  Ideology and adherence to it under any circumstances often prevents us from looking objectively at issues and reaching real solutions, some of which may have winners and losers, but may be necessary to improve long-range forecasts.  Listen to the political patter and decide where the plan is.

For example, ignoring the evidence that the climate is changing, places constituents in perilous positions…..in the future.  Not now and few climate impacts need drastic immediate action.  But longer term, storm sewer will be inadequate, there will be less water stored in glaciers, less rainfall in places (like the southwestern US), more frequent flooding in coastal areas, etc.  The problem may be 50 years from now, but wholesale infrastructure programs take that long.  It took the US 50 years to build the interstate system.  Nearly 40 years to dig canals in south Florida, 20 year to acquire property for a reservoir in North Carolina, etc.  Things take time and meanwhile if we need to alter current practice, such as elevating roadways and building to avoid flooding, the time to start is now, not in 50 years when solving that problem is overwhelming.  Find those water sources now, so development and competitors can be controlled.  Finding water that may take 20 years to secure and construct is an unmanageable issue the year before you need it.  You need a plan.  Where do you hear that planning?

What about that failing infrastructure?  We tend to ignore it until it fails.  But if it fails, that can be catastrophic.  Engineers and operations personnel know deterioration occurs, and know that it will take time to plan, design and refurbish of replace infrastructure.  But projects continue to get deferred for lack of funds.  Aggressively planning repair and replacement may actually save money in the long-run, but our planning tends only to be short-term.  So how do we change that?  Perhaps the state agencies that require local planning to be submitted and approved will push for better evaluation of infrastructure.  GASB 34 clearly did not go far enough.  Too many communities do not track their work and even fewer document the conditions when they make repairs.  Too little data is collected on what fails, when and why.  WE can collect huge amounts of data with work orders that track work.  Perhaps a regulatory frontier.  Or maybe, just maybe, some enlightened managers will decide tracking information is actually fairly easy.  The question is the platform.  Stay tuned… we are working on that…

Highest Risk States for Losses

August 28, 2014
Climate, Colorado, economy, Flooding, infrastructure, sea level rise, sustainability
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As those of you who follow this blog know, we periodically touch on climate issues.  Sea level rise is a particularly acute issue here at ground zero – southeast Florida.  But as I have said for some time, this is not an immediate crisis, but a slow steady creep that gives us time to adapt to the changes related to sea level rise.  I am optimistic that while we will spend a lot more money to engineer water management so we will need more engineers, there are solutions that will allow us to thrive here for a long time – probably a lot longer than we have been here, which is just over 100 years.

Our bigger, current challenge is the temporal but catastrophic impact of tropical storm activity that can create immediate consequences that last for years, much as Hurricane Andrew did in 1992 and Hurricane Wilma almost ten years ago.  Of course there have been others, like Donna in 1960 which were worse.  I mention this because the peak of hurricane season in Sept 10 – only two weeks away.  We have been lucky for years now, and of course we are all hoping it remains that way.

But I found another interesting article this weekend hat talked about the states with the most weather losses since 2006 (and in a subsequent blog I will look back further for comparison). is New Jersey.  OK, no huge surprise given the recent experience of Sandy.  But who is number 2?  Or for that matter 2-10?  Would you believe that Florida is not on the list at all.  Neither is California despite the fires.  Or North Carolina another hurricane prone state.

No, according to the Tribune, the states  (in order:after  New Jersey) are: Texas, Tennessee, Missouri, Alabama, Oklahoma, Mississippi, Louisiana, Colorado and Arizona.  The most common causes: thunderstorms, heavy rain, flash flood and tornados.  And the impacts range from $24 billion in New Jersey to $3.5 billion in Arizona.  An interesting factoid as we approach the peak of hurricane season.  May Florida stay off the list.

Sea Level Rise Planning Part 2

June 26, 2014
Climate, communciations, economy, engineering, Environment, Flooding, infrastructure, innovation, Leadership, local government, management, planning, politics, Risk, Risk Management, sea level rise, stormwater, Uncategorized, utilities, water sewer management
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In the last blog we discussed 10 planning steps for sea level rises.  When planning 50-100 years other factors can come into play as well.  As a result, 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 is suggested.  Hence infrastructure is built to meet milestones, not arbitrary dates lessening the potential for stranded assets.. The increments can work as threshold values in planning considerations in terms of allowing planners the ability to know ahead of time where the next set of vulnerable areas will be to allow a for proactive response approach that can be matched to the observed future sea levels.

But prior to developing infrastructure plans, the local community needs to define an acceptable level of service (LOS) for the community. A level service would indicate how often it is acceptable for flooding to occur in a community on an annual basis.  1% is 4 days per years and for a place like Miami Beach, this is nearly 2 ft NAVD88, well above the mean high tide.  The failure to establish an acceptable LOS is often the cause of failure or loss of confidence in a plan at a later point in time.  The effects of SLR of the level of service should be used to update the mapping to demonstrate how the level of service changes, so that a long-term LOS can be defined and used for near-term planning.

With the LOS known, the vulnerability assessment is developed using a GIS based map of topography and the groundwater levels associated with wet and dry season water levels.  LiDAR is a useful tool that may be available at very high resolution in coastal areas.  Topographic maps must be “ground-truthed” by tying it to local benchmarks and transportation plans.  USGS groundwater and NOAA tidal data from local monitoring stations to correlate with the groundwater information. Based on the results of these efforts, the GIS-based mapping will provide areas of likely flooding.

GIS map should be updated with layers of information for water mains, sewer mains, canals, catch basins, weirs and stormwater facilities.  Updating with critical infrastructure will provide a view of vulnerability of critical infrastructure that will be funded by the public sector. Ultimately policy makers will need more information to prioritize the needed improvements.  For example, a major goal may be to reduce Economic Vulnerability.  This means identifying where economic activity occurs and potential jobs.  At-risk populations, valuable property (tax base) and emergency response may be drivers, which means data from other sources should be added.

The next step is to analyze vulnerability spatially, by overlaying development priorities with expected climate change on GIS maps to identify hotspots where adaptation activities should be focused. This effort includes identification of the critical data gaps which, when filled, will enable more precise identification of at risk infrastructure and predictions of impacts on physical infrastructure and on communities. The final deliverable will include descriptions of the recommended concepts including schematics, cost estimates, and implementation plan.

So why go through all this.  Let’s go back to the beginning.  It has to do with community confidence in its leaders.  Resident look at whether their property will be protected.  Businesses look at long-term viability when making decisions about relocating enterprises.  The insurance industry, which has traditionally been focused on a one year vision of risk, is beginning to discuss long-term risks and not insuring property rebuild is risk-prone areas.  That will affect how bankers look at lending practices, which likely will decrease property values.  Hence it is in the community’s interests to develop a planning framework to adapt to sea level rise and protect vulnerable infrastructure through a long-term plan.  Plan or….

Sea Level Rise, SE Florida Style

May 6, 2014
Climate, economy, engineering, Flooding, funding, infrastructure, planning, politics, sea level rise, sustainability, Uncategorized, utilities, water sewer management, water supplies
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There has been significant discussion about the potential impacts of climate change on the world:  more intense rainfall events, more severe thunderstorms and tropical cyclones, droughts, loss of glacial ice and storage, increased demand for crop irrigation.  However for much of the State of Florida, and for much of the coastal United States east of the Rio Grande River, the climate issue that is most likely to create significant risk to health and economic activity is sea-level rise.  Data gathered by NOAA from multiple sites indicates that sea level rise is occurring, and has been for over 100 years. About 8 inches since 1930.

The impact of climate change on Florida is two-fold – Florida often is water-supply limited as topography limits the ability to store excess precipitation for water use during the dry periods and sea level rise will exacerbate local flooding.  The highly engineered stormwater drainage system of canals and control structures has effectively enabled management of water tables and saltwater intrusion by gravity. The advent of sea-level rise will present new challenges, because the water table is currently maintained at the highest possible levels to counter saltwater intrusion, while limiting flood risk in southeast Florida’s low-lying terrain and providing for water supplies.  As sea level rises, the water will not flow by gravity, which disrupts that balance struck between flood risk and water supply availability in the canal system.

Occasional flooding is not new to Florida, but the increasing frequency we currently experience is related to sea level rise, not just along the coast, but for large expanses of developed property inland due to topography and groundwater levels.  As a result, the challenge for water managers in the state, especially in southeast Florida, is to control the groundwater table, because control of the water table is essential to prevent flooding of the low terrain.

The issue is not lost on local governments in south Florida nor on the educational institutions in the area.  Florida Universities are studying the impacts to the region to identify ways in which we can mitigate, respond to and adapt to these changes. My university, Florida Atlantic University, is located in this vulnerable part of the State has been proactive in partnership with the Four County Compact in addressing these issues and we have now joined with other Universities in the State to form the Florida Climate Institute, a consortium working with state and federal agencies to address the multiple challenges and opportunities facing this State. FAU in particular, has been proactive in developing tools to evaluate risk and identify adaptation strategies to protect local and regional infrastructure and property. 

Our efforts have included using high resolution NOAA data to map topography at the +/- 6 inch level, combined that topography with mapping of infrastructure and groundwater, to identify vulnerable areas throughout Broward, Miami-Dade and Monroe Counties, as well as initiated projects in Palm Beach County and other coastal regions throughout the state.  By identifying vulnerability based on sea level changes, the timing and tools for adaptation can be designed and funded to insure a “no-regrets” strategy that neither accelerates nor delays infrastructure beyond its need. 

While we have all heard the discussion of an estimated two to three feet if sea level rise is anticipated by 2100; sea level rise is a slow, albeit permanent change to our environment.  The slow part allows us to make informed decisions about adaptation strategies that may prove useful in the long term as well as the short term.  Of prime importance is the need to plan for these needs 50 or more years out so that we do not increase our exposure to risk.  Keeping development out of low lying areas, redeveloping pumping and piping systems with change in mind and reserving areas where major efforts will need to be undertaken, is important to the public interest and will affect private business, tourism and homeowners.  Sea level rise is already a problem for many low lying areas such as Miami Beach, Fort Lauderdale, Hollywood, and other coastal communities. It will be an incremental problem creeping up on us for the rest of the century and beyond.

The lowest lying areas are the roadways, which are also the location of electrical, water, sewer, phone and drainage infrastructure.  Fortunately given the current Federally funded special imagery and NOAA data systems we are able to predict pretty accurately where flooding will occur.  Linking that information with detailed projections of sea level rise impacts we can  map vulnerable areas and build adaptive measures into every action and plan we undertake.  But the impacts are not only on the coast. Sea level affects ground water table levels and with our intense rainfall areas far inland can be flooded, even subject to long term inundation.  Water levels are rising and will continue to rise as groundwater rises concurrently with sea level. Add the impact summer rains and dealing with water becomes a major priority. Figures 1 and 2 outline the roadway network degradation at present, 1, 2, and 3 ft of sea level rise.  The figures demonstrate that a major, underestimated amount of property is vulnerable on the western edge of the developed areas because the elevations are decreasing as one moves west from I95. 

Image

While time will impact our environment, there are three options to address the change:

 

  • Protect infrastructure from the impacts of climate change
  • Adapt to the changes, and
  • In the worst case retreat from the change.

 Retreat does not need to be considered in the short or medium term.  South Florida has developed in the last 100 years and there will be well over 100 years of life left.  As a result, the best option is adaptation.  Adaptation takes different forms depending on location.  I have developed a toolbox of options that can be applied to address these adaptation demands, resulting in an approach that will need a more managed integrated water system, more operations and inevitably more dollars.  For example we can install more coastal salinity structures, raise road beds, abandon some local roads, increase storm water pumping, add storm water retention etc. to address many of the problems.  The technology is available today.

Much of the actual needs are local, but the problem is regional and requires a concerted effort of federal, state and local agencies and the private sector to address the scales of the problem.  A community can address the local problems, but the regional canals, barriers, etc., are beyond the scope of individual agencies.  Collaboration and discussion are needed. 

The needs will be large – in the tens of billions.  But there are two things in south Florida’s favor – time and money.  The expenditures are over many, many years.  Most important in the near term need is the early planning and identification of critical components of infrastructure and policy needs and timing for same.  That is what FAU does best.  At risk are nearly 6 million of Floridians their economy and lifestyle, $3.7 trillion in property (2012) in south east Florida alone and a $260 billion annual economy.  All of these are expected to continue to increase assuming the appropriate plans are made to adapt to the changing sea level.  Protection of the area for the next 100-150 years is achievable as long as we have the science, the understanding and the will to do it.  Plan now, and over the rest of this century starting now we can raise those billions of dollars needed.

 

Top Ten Reasons to Deny Climate Change is Occurring in no Particular Order

April 24, 2014
borrowing for infrastructure, Climate, Development loans, economy, engineering, Environment, finance, funding, infrastructure, innovation, Leadership, local government, management, planning, Revenues, sea level rise, stormwater, Transportation, utilities, Water Funding, water sewer management, water supplies, Water treatment
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I had to share this, from a nonscientific survey of people adamantly opposed to any consideration of changes to our climate:

1. I can’t do anything about it so I don’t care about it
2. People can’t alter what is happening with the earth because it is too big
3. It’s natural, so we can’t do anything about it
4. It’s not an issue now, so it’s somebody else’s future problem
5. The science is inconclusive so why do anything yet. Let’s see what happens
6. Trying to address it will cut jobs
7. We won’t be competitive (i.e our profits will drop)
8. It requires changing our business model (energy)
9. If we talk about it no one will develop in our community
10. Costs too much

I had to post this as many of you will have comments. But before you do, these about this a minute……

The first five are based on no facts, but a desire to ignore the issue entirely. The second five are more poignant because aren’t these pretty much the same arguments to deny the need to correct water pollution concerns in the 1930s? Or 1950s? Or even 1970s? Or even today with hog farms, frack water, acid mine waste, coal dust slurries, etc.? Or actually pretty much every regulation? I seem to recall Tom Delay making this argument when he was in Congress before he was indicted.

Now think about the Clean Water Act, Clean Air Act, Safe Drinking Water Act, and others. These regulations are designed to correct ills of the past that were simply ignored due to the first five arguments above, ignoring the fact that prevention is always less costly than cleanup afterward. To we pass regulations to clean up problems and protect the public health going forward. Otherwise why have a regulation?

So let’s talk about that jobs impact. The reason is that after the passage of these regulations, didn’t the number of professional jobs (like civil and environmental engineers, environmental and other scientists – STEM jobs) increase? Isn’t increasing STEM jobs a priority? So won’t dealing with climate issue perhaps create a similar increase in STEM jobs? Yes, costs for water increased and the cost for the effects of climate changes will cost money, but don’t these challenges create opportunities? Isn’t this akin to dealing with problems with development from the past? Just asking…..

SEA LEVEL RISE AND FLOOD PROTECTION

February 12, 2014
communciations, Flooding, funding, infrastructure, Leadership, local government, management, planning, politics, Revenues, sea level rise, stormwater, sustainability, Tidal flooding, Uncategorized, utilities
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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). 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.

Why is this relevant?  The City of Fort Lauderdale reported last week that $1 billion will need to be spent to deal with the effect of sea level rise in Fort Lauderdale alone.  Fort Lauderdale is a coastal city with canals and ocean property, but it is not so different from much of Miami-Dade County, Hollywood, Hallandale Beach, Dania Beach and host of other coastal cities in southeast Florida.  Their costs may be a harbinger of costs to these other communities. Doing a “back of the napkin”  projection of Fort Lauderdale’s cost for 200,000 people to the additional million people in similar proximity to Fort Lauderdale means that $5 billion could easily be spent over the next 100 years for costal impoundments like flap gates, pumping stations, recharge wells, storm water preserves, exfiltration trenches and as discussed in this blog before, infiltration galleries. Keep in mind that would be the coastal number and we often ignore ancillary issues.  At the same time, an addition $5 to 10 billion may be needed for inland flooding problems due to the rise of groundwater as a result of SLR.

The question raised in conjunction with the announcement was “is it worth it?”  I suggest the answer is yes, and not just because local politicians may be willing to spend money to protect their constituents.  The reality is that $178 billion of the $750 billion economy of Florida, and a quarter of its population, is in the southeast. With nearly $4 trillion property values, raising a few billion for coastal improvements over 100 years is not an insurmountable task.  It is billions in local engineering and construction jobs, while only impacting taxpayers to the tune of less than 1/10 of a mill per year on property taxes. This is still not an insurmountable problem.

I think with good leadership, we can see our way.  However, that leadership will need to overcome a host of potential local community conflicts as some communities will “get more” than others, yet everyone benefits across the region.  New approaches to working together will need to be tried.  But the problem is not insurmountable, for now…

COLORADO IS DRY, WELL NOT ANYMORE

September 16, 2013
Drought, economy, engineering, Flooding, infrastructure, Insurance, Leadership, management, stormwater, sustainability, Uncategorized
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I went to Colorado in July, and it was bone dry like I noted in a prior blog.  The trend was expected to continue, but then something happened.  It rained.  A lot. It’s been raining for almost a month.  Last week it was wet out there, really wet, devastatingly wet on the east side of Rocky Mountain National Park (Boulder, Estes Park, Longmont, Lyons). The rain has not really let up so mountain streams are over-running their banks, flooding streets, washing away bridges, damaging property and businesses.  Helicopter evaluation of the damage indicates that miles of roadways are badly damaged. Route 34/36, the primary eastern entrance to Rocky Mountain National Park may have 17 miles (of 20) damage pavement and foundation needing immediate repair.  Estes Park is cut off from the world and there was mud in the streets.  Rocky Mountain National Park is closed to allow access from Grand Lake for emergency vehicles, residents and supplies.  And eastern emergency route from Nederland is also available.  Tourism has halted in the peak of Fall tourist season.

How fortunes have changed, and continue to change.  Three years ago it was the west side of Colorado with 300 inches of snow that flooded downstream communities.  Three months ago was drought. Are these changes part of a larger issue, or a continuation of the status quo?  Hard to know, but certainly both events were far above any prior events experienced in the area.  The local infrastructure was not constructed to meet these conditions, so either the climate is changing, our models are wrong, or both.  We see the same issue playing out regularly around the world when the 100 year or 500 year storm event occurs and wreaks havoc on a community which does not have infrastructure planned for events like this.

 Expect NE Colorado to be a federal disaster area.  Expect billions to be spent on reconstruction of roadways.   But the larger question is whether the new, replacement infrastructure will survive a similar, or larger climate event in the future.  Will our infrastructure planning be short sighted or will it be adjusted accordingly?  The potential for us to protect infrastructure, and property is completely related to our ability to adjust to infrastructure needs and to minimize exposure to weather events.  Keep in mind our economy and way of life is directly related to our infrastructure condition.  But people want to live near rivers and streams, but rarely consider the real risk and consequences. 

How do we address these risks?  FEMA evaluates the probability of flooding to set flood insurance, but FEMA does not prevent construction in flood zones.  Where construction can occur is a state or local issue.  Of course, few local entities want to limit development in any way, so we keep putting people at risk.  Local officials, like those in Florida, keep pushing FEMA officials to reduce flood risks, despite evidence of increasing rainfall intensity that would increase flooding.  Florida is not alone.  No doubt Colorado officials have the same views.  We need to impress upon local officials the risks and encourage them to reduce risks to citizens.  It’s our tax money and insurance premiums they are raising.  But they are rarely held accountable.  Nor are non-elected officials.  Somehow, this needs to change.  We need leaders to stand up and draw the  line in the sand.

REVISING OUR VIEW OF INFILTRATION GALLERIES IS SOUTH FLORIDA

July 13, 2013
Climate, Environment, groundwater, infiltration, infiltration gallery, infrastructure, innovation, Leadership, management, sea level rise, sustainability, Tidal flooding, water sewer management, water supplies
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A recent Rolling Stone article outlines a potentially dismal future for south Florida.  I was quoted in the article and give the author a bunch of information.  It is hard to write articles that “pop” in the popular press while conveying facts and figures.  But I would suggest that the future is not quite as dismal as the article depicts.  The sea level rise has been ongoing for at least 140 years as indicated by the Key West tidal station, the longest running tidal gauge in the world, but the amount has been 9 inches since 1920.  True it appears that the sea level rise may be accelerating as a result of warming temperatures in the atmosphere that causes the oceans to expend, plus the loss of ice that runs off from glaciers, but 3 feet by 2100 seems the average or maybe the high average.  That is unlikely to inundate all of south Florida, but keeping the water table low will be a challenge.  I suggest that the challenge can be met and accomplish two goals.  In low lying areas the impact of sea level rise is really manifested as increasing groundwater tables.  An increased groundwater table means less soil storage capacity, which means smaller rainstorms will cause flooding.  The increased flooding is already creating a demand by residents for solutions from local public officials.  We have used exfiltration trenches (French drains) for many years, but increasing water tables will mean many of these systems will not function as they may be currently.  But what if we reverse the concept?  Instead of exfiltration, what if we allowed the water to infiltrate the pipe and go to a central wet well, and then pump the water out of the wet well?  I further suggest that the dumping large quantities of groundwater to the ocean or canals may not be permittable as a result of high nutrients, so what if this water is instead pumped to a water plant as a raw water supply?  Wouldn’t that solve two problems at once? Lots of excess fresh water supplies in an era where there are significant limitations in fresh water supplies?  Just thinking….. 

 

 

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