The floods of 1929 and 1935 in the White Oak and Buffalo Bayou watersheds devastated downtown Houston.  They led to the creation of the Harris County Flood Control District and the Congressional authorization and appropriation of federal dollars to the US Army Corps of Engineers (USACE) to devise a plan to address flooding the Houston area.

The 1940 plan included Addicks, Barker, and White Oak reservoirs; a diversion levee along Cypress Creek (to prevent its water from overflowing into the areas draining to Addicks and Barker; the channelization of about 7 miles of Buffalo Bayou (between what is now Highway 6 and about S. Piney Point); a 2 mile long Brickhouse Gully Bypass Channel; a 25 mile long North Canal; and a 35 mile long South Canal (see plan below).

Can you identify which parts of the plan were constructed and which parts were not?

The levees built to create Addicks and Barker are not like traditional dams. Traditional dams, in places where the ground surface elevation changes radically (think Hoover Dam on the Colorado River near Las Vegas), dams can be 100’s of feet tall and made from reinforced concrete.  The water pressure against the bottom of the Hoover Dam at max pool depth is 255 pounds per square inch.  Addicks and Barker are very squat comparatively. They are made from compacted layers of dirt in a backwards facing letter “C” configuration.  They were built on ground that gently slopes to the northwest, but they were built to have horizontal tops at the same or similar elevations (except the ends).  The ends were tapered to meet the ground.  These ends were covered in a protective layer of concrete so the tapered portions could serve as emergency spillways in the event that the water collected behind the levees got too high.  Each taper is at a different elevation to make sure the rate of spillage only gradually increases (since all of the water is going to the same bayou) instead of gushing out both sides at once.  See the diagram below.

The following two diagrams provide a close-up, cross-sectional view of one of the levees. The first shows the viewing direction of each of the cross-sections, A-A and B-B.

The second shows the actual views, which hypothetical water levels illustrating the emergency spillway operation.

Many have asked me why residential and commercial development was allowed to occur to the west of the impoundment area. I think there were and are a variety of reasons.

First, the impoundment area was originally sized with the expectation that the blue conveyance systems shown in the graphic above would be constructed and that the White Oak Reservoir would be constructed to reduce the volume of water conveyed by the lower section of Buffalo Bayou. This led to the federal government only buying the acreage they thought they needed – given the discharge capacity of the blue conveyance system.

Second, as time wore on, and the city grew, the privately owned land to the west of each reservoir was not purchased by any government entity for the purpose of flood damage mitigation.  If this had been done, the land could have been set aside for that purpose.

Third, if there is one thing I’ve learned about Texans, after living here for 20 years, they value their individual property rights. This culture made it unlikely that any local government would restrict land use in the land upstream of the reservoir land.

Fourth, our laws and regulations governing real estate transactions don’t appear to require disclosure of information about flood risk unless the risk is equal to or greater than a 1% annual chance of flooding. This means that thousands of people bought homes in the area just west of the federally owned land and did not know about the flood risk associated with those locations.  Although the risk is less than 1% each year (which, as I written elsewhere, gives your home a 26% chance of flooding during a 30 year mortgage), it’s not zero.

Others have asked me why the rest of the 1940 plan was not built. I don’t know the actual answer to that question, but I suspect World War II may have had something to do with it. Also, it’s possible that some combination of local funding and Congressional funding did not materialize as planned.

Over the last week there’s been some discussion about making the levees higher, excavating the inundation pool areas deeper, or a combination of both. What do you think about these ideas?

[Update on September 7, 2017 – Added National Academy of Sciences Report on Attribution of Extreme Weather Events in the Context of Climate Change]

I wonder if Harvey was caused (or made worse) by climate change?

Now that I have your attention….

I previously have written a bit on whether or not certain studies of rainfall history suggest that extreme events are becoming larger or more frequent.  Here’s a quote from my op-ed in Trib-Talk from February 2017:

Our region has also been looking at the effect of climate change on rainfall patterns. In March 2016, Harris County joined a national study by the National Oceanic and Atmospheric Administration [NOAA] to recalculate the 1 percent storm size for Texas using rainfall records from a longer period of time. Similar work completed for the southeast and southwest regions of the country [by NOAA] showed that rainfall depths over time did not have statistically significant trends up or down — i.e., no climate-change effect was observed on those types of storms.

Since I reported on what NOAA did in New Mexico and Louisiana, many folks have apparently taken this to mean that I don’t believe in climate change. To set the record straight, here’s what I think about climate change and how we might deal with it.

Climate change will require us to do three things, in amounts that relate to each other:

1. Mitigate: Reduce the amount of carbon we emit. Hopefully we will do this using market forces and creativity. This might be done by establishing a cap on emissions and a price for the right to emit a certain mass of carbon. This would then create a business case for reducing carbon emissions, sequestering carbon, or otherwise controlling carbon and then selling the right to emit some.
2. Adapt:  Change our planning and design approach for infrastructure, development, and just about everything else we do, to account for anticipated future conditions. This could be wind speeds, rainfall intensities, rainfall depths, rainfall frequencies, sea levels, solar radiation, temperature, etc. Think where and how we grow food. How we get around.  How we plan development.  The size and materials used for infrastructure.  This also might also include retrofitting existing systems.
3. Suffer: Deal with the social, environmental, and economic consequences of the anticipated changes, many of which will be negative and will be felt mostly by lower income people. This might be water scarcity, flooding, new diseases, sea level rise, storms, more costly food, more costly transportation, etc.  Of course suffering will cost money also.

The amount of energy, thought, and time we put into each of these three things will depend on how much energy, thought, and time we put into the other two.  If we don’t mitigate or adapt, than suffering will increase.  If we mitigate a lot, then the required adaptation effort will go down a bit and the suffering will diminish.  This is not a new way to conceptualize our situation. I’m stealing this from some other much more well informed people.

Now, lets focus on development and drainage in the Houston area.

If you review historic rainfall amounts up through today, you can see statistically significant increasing trend lines for smaller rainfall amounts. For example, the number of days per year experiencing more than 3″ of rain is increasing over time. This suggests that the number of 12″ days or 13″ days (about equal to the current 1% annual chance event) is increasing, even though those events are so rare we can’t see the trend in only 70 years of data. That’s because, by definition, we would expect to only see one such event in 100 years of data. Hard to see a time series trend in one data point, right?

Now if we see increasing trends in 3″ days (which are very common), 4″ days, and 5″ days, then we can extrapolate the data for both smaller storms and larger storms out to any future year to see what kind of rainfall we can expect and what kind of stormwater management and floodplain management we should undertake. Thanks to Matt Berg and Katharine Hayhoe for this insight.

So in Houston we currently design stormwater systems to handle 12″ days, which is the depth of rain that has a 1% chance of occurring every year (based on the last time we calculated this value).  Let’s say we update our analysis of rainfall data and we find that the current 1% annual chance is actually a 14″ day.  Let’s further assume that we estimate that the 1% annual chance event in the year 2067 will be 16″ day (based on our extrapolated increasing trend line).  If these assumptions were true then we have the technical information to inform some important policy choices.

First, we would need to decide what level of risk we would like to use to design new infrastructure and developments. Perhaps we would want to change from a 1% annual chance level of service to a 0.5% annual chance level of service? This would mean that our designs would need to accommodate more rain in a single day. Building to a lower risk level would require a higher initial investment, but might reduce overall life-cycle costs, especially if repair and replacement probabilities were factored in.

Second, we would need to decide, based on the facility’s design life, what future conditions we should consider. A facility in operation in 2067 that needed a 1% annual chance risk level should be designed to handle the hypothetical 16″ day mentioned above.  A facility designed for a 10 year life might be designed to handle the current or short term predicted increase in the 1% annual chance rainfall.

Lastly, and perhaps most importantly, we would need to find the money to invest in retrofitting or modifying the older portions of our city that don’t currently meet our existing 1% annual chance rain event, much less the 1% annual chance event predicted to occur in 2067.

We can figure this stuff out. We just need to do it.

Oh, what about Harvey, which delivered four day rainfall totals depicted in the image below, from Harris County Flood Control District’s Flood Warning System.

Well there is an entire science used to determine how to attribute a particular outcome to certain input variables. Attributing any particular event to human-caused climate change depends upon the time scale and geographic size of the event being studied. I direct you to this paper about whether the August 2016 flooding in Louisiana was due to climate change and to the National Academy of Sciences report Attribution of Extreme Weather Events in the Context of Climate Change for additional insights and details.

I tend to think that human-caused climate change increased the probability of Harvey occurring, but I personally don’t have a way to estimate the magnitude of that increase. Perhaps some statistics experts and climate scientists can help us out?

[Update on September 7, 2017 – Added National Academy of Sciences Report on Attribution of Extreme Weather Events in the Context of Climate Change]

[Direct quote re-posted from The Atlantic…]

August 5, 2017

Can Congress Bring the National Flood Insurance Program Above Water?

The debate over too-low premiums and repetitive payouts grinds on, even as the thunderheads roll in and the water levels rise.

By Michelle Cottle

Get those sandbags and storm shutters ready. Peak hurricane season is bearing down on the Atlantic coast. From New Orleans to the Jersey Shore, nothing focuses the mind quite like a looming megastorm. And while this time of year is always meteorologically suspenseful, now it’s even more so. That’s because among the many, many things Congress is struggling to cross off its to-do list is the reform and reauthorization of the National Flood Insurance Program (NFIP).

As problematic government programs go, the NFIP is a doozy. Established in 1968, it handles some 5 million policies nationwide. Unfortunately, these days it collects less in premiums and surcharges than it shells out in claims and other expenses, leaving the Treasury Department—read: taxpayers—to plug the holes. Which means every time some neighborhood in Galveston or Daytona winds up underwater (Texas, Florida, and Louisiana account for more than half of all policies), the rest of the nation effectively bails them out. Not that coastal areas bear all the blame—rivers have a nasty habit of overflowing as well. Last August, an ugly storm parked itself over Baton Rouge for several days, dropping upwards of 20 inches of rain that caused $10 billion in damages. All told, the FEMA-managed NFIP is neck-deep in debt to the tune of $24.6 billion.

The structural, some even say moral, flaws of NFIP are vast and varied. 

[Direct quote re-posted from The Atlantic…]

[Read more]

Newspaper or online story headlines:

• Potable Water System Continues to Provide Safe and Affordable Water to Millions
• Drainage System Safely Conveys Another Rain Event Away From Millions of Residents
• Transportation Network Allows Millions to Get to Work and Produce Regional Economic Value
• Millions Live and Work In Comfort Inside Electrically Powered Air Conditioned Environments

Ever see headlines like these?  No. I didn’t think so.

As we’ve seen more acutely in the last few years, news is product for sale. It’s packaged and designed to appeal to a certain customer. It features stories and subjects that people will find interesting, emotional, and attractive. It features stories that will “sell.” It features stories that attract buyers looking to confirm their world view.

“Nothing bad happened today” is not a story that will sell very well. Stories about public infrastructure systems that work the vast majority of the time do not sell newspapers or generate online clicks.

I recently attended the West Houston Association’s Flood Control Technical Forum, which featured the Executive Director of the Harris County Flood Control District, Russ Poppe, and City of Houston Chief Resiliency Officer, Steve Costello.

Mr. Poppe showed a slide which listed the number of homes flooded in each of several watersheds during the Tax Day and Memorial Day floods of 2015 and 2016. They were large numbers. As “just” numbers, they did not fully convey the horrible negative emotional, physical, financial, and social impacts those large rain events (and the inability of the drainage systems to convey the resulting large amount of stormwater runoff) had on the people who flooded. The stories of the people who flooded are raw, emotional, visceral, and terrible. The photographs of flooded homes are powerful.

But the slide also included the number of homes that did NOT flood because of drainage system improvements constructed in each of the watersheds before the rains came.  Here’s the slide:

When we total the totals, here’s what we get:

• Homes flooded from two large rain events: 5,750.
• Homes NOT flooded from two large rain events because of infrastructure improvements designed and built by Harris County Flood Control District: 14,385.

This is great news, especially given that the HCFCD is funded with revenue from an annual property tax rate of about $0.028 per $100.00 valuation. [This means that a family living in a home valued at $100,000 will contribute about $28.00 each year to HCFCD revenues.] That’s about $2.33 per month.

Just image the flood damage reduction and flood risk reduction we could accomplish if we could find a few more dollars a month in funding.

The Set Up

Say you have a contract to purchase land at a great price in a great location for a new development project. The financial projections for the project (both costs and revenues) look great and the internal rate of return meets your investment requirements. All looks promising, except, during due diligence, someone mentions that there might be wetlands in the planned development area.

What to do next depends on how much risk you and your financial backers can stomach. It is a violation of federal law to impact waters of the United States without a permit. If your project is self-financed and you are a risk taker, you might decide to move forward with little to no field work and coordination with the U.S. Army Corps of Engineers (USACE). If you have a traditional loan or work for a publicly traded company you might move forward after more extensive field work and coordination with the USACE, including a permitting step.

Wetlands assessments can range from an inexpensive Desktop Evaluation up to a full, Wetlands Delineation using USACE procedures and forms. For a 500 acre, partially forested tract, these services might range from several thousand dollars to the high two figures. The amount you spend should depend upon your tolerance for risk and how much capital must be committed at that moment in the process.

Desktop Evaluation

A Desktop Evaluation considers readily available historical and current aerial photos, floodplain maps, and the US Fish and Wildlife’s National Wetlands Inventory (NWI) maps.  This is the least expensive method, but its also is the least accurate and least defensible method should questions arise after the development is constructed.  A Desktop Evaluation is not sufficient to secure an official ruling from the USACE on the regulatory status of the wetlands. NWI wetland polygons may or may not represent an actual wetland due to the age of the satellite imagery used to produce them and because ground surface vegetation and hydrology may be obscured.  Historical aerial photographs are also reviewed and they inexpensively provide great insight about the potential for wetlands to be present; however, they are no substitute for direct observation of site conditions.

A Desktop Evaluation is typically a good choice prior to any land purchase. The results can help give you a rough qualitative sense of whether you should spend a bit more investigating what’s really there and how the wetlands might constrain your land plan and revenue forecast. It can also help give you a rough idea about what kind of permitting might be necessary and the schedule impact that might have.

Wetlands Assessment

The next level of investment involves a site visit by a professional wetlands scientist to observe the site directly and to examine the soils, plants, and hydrology in a few locations. This is often called a Wetlands Assessment.  It does not comply with the full delineation requirements imposed by the USACE, however, it does allow the consultant to provide an opinion regarding the location and size of wetlands on the property.  After a Wetlands Assessment the consultant will typically provide a brief report with a refined site map, an estimate of the size and location of wetlands on the property, an opinion about whether they might be under federal jurisdiction (and might trigger permitting if unavoidably impacted), and initial thoughts about permitting options (if anticipated to be required).

The results of a Wetlands Assessment reduces your risk exposure, provides more information on which to base a purchase decision, helps guide land planning decisions, and helps refine project financial projections. The results of a Wetlands Assessment can sometimes justify walking away from a project, especially if extensive federally regulated wetlands are present and permitting unavoidable impacts would be too time consuming or if the replacement of lost wetlands would be too costly.  The results of a Wetlands Assessment can sometimes justify proceeding with the project without USACE coordination or permitting if the Wetlands Assessment shows no unavoidable impacts that would require permitting.

 Wetlands Delineation

A Wetlands Delineation evaluates soils, hydrology, and vegetation at multiple locations in and around the boundary of each wetland feature to accurately identified the size, location, and shape of each wetland area on the site.  The process is defined in detail in national USACE Guidance (with regional supplements) and the results are presented in USACE forms.  This is the most expensive approach, however, it accurately and precisely defines the location and size of each area of the project that is likely to be subject to federal regulation, in the consultant’s opinion.

A Wetlands Delineation is an extensive study that reduces your risk and liability exposure even more than a Wetlands Assessment.  A Wetlands Delineation also allows you to more confidently estimate the size of any unavoidable wetland impacts your development might create. The accurate wetland map can be used to refine the land plan to avoid and minimize impacts to wetlands. The revised land plan can then be used to update the project financial projections.

Jurisdictional Determination

Not all wetlands or creeks are “Waters of the United States” subject to federal regulation. Your consultant can provide a professional opinion regarding the status of the wetlands and waters on your property; however, the USACE is the only entity that has the legal authority and power to officially determine whether a wetland or waterbody is subject to federal regulation. Please see this post for a primer on how they do this.

If you elect to conduct a Wetlands Delineation, that detailed information can be submitted to the USACE, along with an “Approved Jurisdictional Determination Form” to ask the USACE to verify the delineation and to make a determination regarding the jurisdictional status of all wetlands and waters on your property.

There are actually two kinds of determinations.  An Approved Jurisdictional Determination (AJD) is a final statement as to the status of all wetlands and waters on your site. It is used in cases where there may be some wetlands or waterbodies on your site that are likely not federally regulated, because, for example, they are isolated, or were constructed in the past, or for some other reason. An AJD (hopefully) confirms your consultant’s opinion and gives you permission to impact certain wetlands that are not federally regulated while protecting others that are. This reduces your risk and liability exposure because the entity with the sole legal authority to make the decision, makes the decision in writing, in the form of a “determination letter.”

The second kind of determination is a Preliminary Jurisdictional Determination (PJD). A PJD is typically used if you want to save time and you’ve determined that your project can be developed without any impacts to wetlands or water features and still be financially viable. The PJD, in effect concedes that all wetlands and water features on the property are waters of the United States and that unavoidable impacts to them must be permitted.

A future post will provide an overview of the permitting options offered by the USACE to project sponsors that have unavoidable impacts to waters of the United States.

On July 11, 2017 Leah Binkovitz, a staff writer for the Rice Kinder Institute for Urban Research, published a story on The Urban Edge blog entitled: “Why the 100-Year Floodplain Needs to be Rethought.” This post provides some comments.

The story states that “areas inside the 100-year floodplain have a 1 percent chance of flooding each year and are required to buy federally-regulated insurance. But that measure has been increasingly called into question, along with the role of the flood insurance program.”

The story correctly notes that floodplain managers in the United States have used the 1% annual chance threshold to define the arbitrary boundary between high risk and low risk areas along bayous and rivers since 1968. It is policy decision we’ve made, not a technical one.

It is not true that all structures with an annual chance of flooding of 1% or greater are required to buy flood insurance. There is no law or regulation that requires that. It is almost always required by the lender, in order to replace the structure, which serves as collateral for the loan, if it is damaged in a flood. Owners of structures with an annual chance of flooding lower than 1% are also not required to obtain insurance by regulation or by lenders; but many can and do.

We should encourage discussion about whether the 1% risk level is a good dividing line between “high risk” and “low risk” areas, when, obviously, the risk gradually declines as you move away from each creek or bayou. We should also encourage discussion about the exposure to risk from flooding which occurs in areas outside of bayou floodplains. Local streets and storm drains in neighborhoods can only handle a certain depth of rainfall over a certain period of time. If that, so called, “level of service,” is exceeded, or if drains are clogged or broken, local flooding can occur. Our policy discussion should also consider the public’s risk tolerance and their willingness to pay to reduce their risk exposure.

If we decided to make the policy choice to define the high risk areas as those with a 0.5% or a 0.1% annual chance of flooding, and mandated the purchase of insurance on homes or structures in those areas, what would happen to the size of the floodplain and the community cost burden? It would get much bigger. It would encompass many more homes and structures. Flooding events would trigger more claims and much larger insurance payouts. All of these facts would drastically increase the cost of flood insurance or the cost to federal tax payers, especially in flat, coastal areas like Houston. [This might even be considered analogous to the way the Affordable Care Act mandated the purchase of health insurance so that healthy people (those with a low flood risk) would help subsidize the less healthy people or those with pre-existing conditions (those with a high flood risk).]

The story then describes how many insured losses are located outside the 100-year floodplain, quoting from a study, published online earlier this year and in print in the August issue of Natural Hazards Review.

Why would so many homes and businesses located outside of the 100-year floodplain have flood insurance? Many people obtain insurance on a voluntary basis because it is very inexpensive when compared to risk of loss and the cost of such losses. It is inexpensive because it is subsidized by the federal tax payer (you and me).

The story suggests that floodplain models “don’t take into account changing land use, like loss of wetlands or additional impervious surfaces — both important factors in the fast-growing Houston metropolitan area.”

Floodplains are defined using the most up to date and current information about rainfall intensity and depths, topography, land use, and land cover available at the time. Floodplain models are created by licensed professional engineers using current data and then formally adopted by floodplain administrators. These modeling efforts are extensive and relatively costly, therefore, they are not broadly updated very often. Changes in the watershed outside the floodplain are not addressed until there is restudy of the floodplain associated with that watershed and bayou. So its true we don’t have “real-time” watershed models and floodplain maps. They are only accurate for a short time after they are published in a fast growing watershed. In watersheds without significant development activity, they are accurate for a much longer period of time.

Floodplain models and maps are, however, frequently updated as a result of new development or other changes inside the existing floodplain through a process called a “Conditional Letter of Map Revision (CLOMR)” and a “Letter of Map Revision (LOMR).” The CLOMR is a prediction of the increase or decrease in the base flood elevation and areal extent, before to the project being built. The LOMR revises the map after the project is built. This process allows floodplain managers to update the model as a result of floodplain changes and to inform the affected land owners and communities know about the pending and actual changes. Project Brays is a great local example of this process illustrating the reduction of the floodplain as a result of channel changes.

Wholesale updates of the model for a particular watershed occur less frequently mainly due to funding constraints.  Floodplain managers would conduct these updates more frequently is funding was made available.

So discussions about our risk tolerance, our willingness to pay for reduced risks, our willingness to invest in more frequently updated risk assessments, and who bears the costs of floodplain management and losses are all important.  What do you think?

[July 27, 2017: The proposed rule has been published today’s Federal Register. Comments are due August 28, 2017.]

[July 21, 2017 Update: If you’ve been checking the Federal Register each day you may already know that, surprisingly, this rule has not yet been published.]

On June 27, 2017 the U.S. Environmental Protection Agency (EPA) posted the pre-publication version of their pending Proposed Rule entitled: “Definition of ‘Waters of the United States’ – Recodification of Pre-existing Rules.”  Here’s an extremely brief summary of what has led up to this rule and a short summary of what it proposes to do.

The definition of the term “waters of the United States” — or “WOTUS” for short — has been the subject of much litigation over the years. Its definition determines if a private party needs U.S. Government permission (in the form of a permit issued by the U.S. Army Corps of Engineers) to impact wet areas on their property. The term is used to define “navigable waters” in federal law.

On one end of the spectrum there are traditionally navigable waters used for interstate commerce. These are unquestionably WOTUS.

In the middle of the spectrum there are wetlands adjacent to navigable waters. There are tributaries of navigable waters. There are tributaries of tributaries of navigable waters. There are even wetlands adjacent to these various types of tributaries.

On the other end of the spectrum there are small, isolated areas of standing water, soils, and vegetation (true wetlands) located far away from any navigable waterway.

Which of these is subject to Federal regulation?

That question has been addressed by U.S. Supreme Court cases, EPA Guidance, and regulations. These may be summarized and simplified as follows:

• Riverside (1985): Wetlands adjacent to a navigable water are WOTUS.
• Solid Waste Authority of Northern Cook County  (SWANCC) (2001): Isolated wetlands used by migratory birds (thus triggering an intrastate commerce activity) are NOT sufficient to make an isolated wetlands a WOTUS. A “significant nexus” between the isolated water and a navigable waterway is required for waters to be WOTUS.
• Rapanos (2006): Relatively permanent, standing or continuously flowing bodies of water, that are connected to traditional navigable waters as well as wetlands with a continuous surface connection to such water bodies are WOTUS. Also aquatic features or wetlands must have a “significant nexus” to a WOTUS to be considered a WOTUS. In practice, this made most isolated wetlands, those not adjacent or abutting a navigable water, those not in the floodplain of a waterway, and those not a tributary of a navigable water, typically NOT WOTUS.
• Final Clean Water Rule (2015): Created a prescriptive “significant nexus” test that had the effect of making many isolated wetlands WOTUS.

U.S. Supreme Court AT THE TIME OF THE RAPANOS DECISION (2006).

The Trump administration views the Clean Water Rule as inappropriately extending federal jurisdiction to wetlands and aquatic resources beyond those that would be regulated under the Rapanos decision and associated guidance. This view has led to the proposed rule that was just released. Quoting from the pre-publication Federal Register text:

In this proposed rule, the agencies would rescind the 2015 Clean Water Rule and replace it with a recodification of the regulatory text that governed the legal regime prior to the 2015 Clean Water Rule and that the agencies are currently implementing under the court stay, informed by applicable guidance documents (e.g., the 2003 and 2008 guidance documents, as well as relevant memoranda and regulatory guidance letters), and consistent with the SWANCC and Rapanos Supreme Court decisions, applicable case law, and longstanding agency practice. The proposal retains exclusions from the definition of “waters of the United States” for prior converted cropland and waste treatment systems, both of which existed before the 2015 regulations were issued. Nothing in this proposed rule restricts the ability of States to protect waters within their boundaries by defining the scope of waters regulated under State law more broadly than the federal law definition.

Once the proposed rule is published in the Federal Register the public will have 30 days to submit comments. I’ll update this post with a link to the docket when it becomes available.

[July 27, 2017: The proposed rule has been published today’s Federal Register. Comments are due August 28, 2017.]

[July 21, 2017 Update: If you’ve been checking the Federal Register each day you may already know that, surprisingly, this rule has not yet been published.]

Declaration of Independence

Note: The following text is a transcription of the Stone Engraving of the parchment Declaration of Independence (the document on display in the Rotunda at the National Archives Museum.) The spelling and punctuation reflects the original.

In Congress [Philadelphia, Pennsylvania], July 4, 1776.

The unanimous Declaration of the thirteen united States of America,

When in the Course of human events, it becomes necessary for one people to dissolve the political bands which have connected them with another, and to assume among the powers of the earth, the separate and equal station to which the Laws of Nature and of Nature’s God entitle them, a decent respect to the opinions of mankind requires that they should declare the causes which impel them to the separation.

Independence Hall, Philadelphia, PA. Source: National Park Service.

We hold these truths to be self-evident, that all men are created equal, that they are endowed by their Creator with certain unalienable Rights, that among these are Life, Liberty and the pursuit of Happiness.–That to secure these rights, Governments are instituted among Men, deriving their just powers from the consent of the governed, –That whenever any Form of Government becomes destructive of these ends, it is the Right of the People to alter or to abolish it, and to institute new Government, laying its foundation on such principles and organizing its powers in such form, as to them shall seem most likely to effect their Safety and Happiness. Prudence, indeed, will dictate that Governments long established should not be changed for light and transient causes; and accordingly all experience hath shewn, that mankind are more disposed to suffer, while evils are sufferable, than to right themselves by abolishing the forms to which they are accustomed. But when a long train of abuses and usurpations, pursuing invariably the same Object evinces a design to reduce them under absolute Despotism, it is their right, it is their duty, to throw off such Government, and to provide new Guards for their future security.–Such has been the patient sufferance of these Colonies; and such is now the necessity which constrains them to alter their former Systems of Government. The history of the present King of Great Britain is a history of repeated injuries and usurpations, all having in direct object the establishment of an absolute Tyranny over these States. To prove this, let Facts be submitted to a candid world.

• He has refused his Assent to Laws, the most wholesome and necessary for the public good.
• He has forbidden his Governors to pass Laws of immediate and pressing importance, unless suspended in their operation till his Assent should be obtained; and when so suspended, he has utterly neglected to attend to them.
• He has refused to pass other Laws for the accommodation of large districts of people, unless those people would relinquish the right of Representation in the Legislature, a right inestimable to them and formidable to tyrants only.
• He has called together legislative bodies at places unusual, uncomfortable, and distant from the depository of their public Records, for the sole purpose of fatiguing them into compliance with his measures.
• He has dissolved Representative Houses repeatedly, for opposing with manly firmness his invasions on the rights of the people.
• He has refused for a long time, after such dissolutions, to cause others to be elected; whereby the Legislative powers, incapable of Annihilation, have returned to the People at large for their exercise; the State remaining in the mean time exposed to all the dangers of invasion from without, and convulsions within.
• He has endeavoured to prevent the population of these States; for that purpose obstructing the Laws for Naturalization of Foreigners; refusing to pass others to encourage their migrations hither, and raising the conditions of new Appropriations of Lands.
• He has obstructed the Administration of Justice, by refusing his Assent to Laws for establishing Judiciary powers.
• He has made Judges dependent on his Will alone, for the tenure of their offices, and the amount and payment of their salaries.
• He has erected a multitude of New Offices, and sent hither swarms of Officers to harrass our people, and eat out their substance.
• He has kept among us, in times of peace, Standing Armies without the Consent of our legislatures.
• He has affected to render the Military independent of and superior to the Civil power.
• He has combined with others to subject us to a jurisdiction foreign to our constitution, and unacknowledged by our laws; giving his Assent to their Acts of pretended Legislation:
• For Quartering large bodies of armed troops among us:
• For protecting them, by a mock Trial, from punishment for any Murders which they should commit on the Inhabitants of these States:
• For cutting off our Trade with all parts of the world:
• For imposing Taxes on us without our Consent:
• For depriving us in many cases, of the benefits of Trial by Jury:
• For transporting us beyond Seas to be tried for pretended offences
• For abolishing the free System of English Laws in a neighbouring Province, establishing therein an Arbitrary government, and enlarging its Boundaries so as to render it at once an example and fit instrument for introducing the same absolute rule into these Colonies:
• For taking away our Charters, abolishing our most valuable Laws, and altering fundamentally the Forms of our Governments:
• For suspending our own Legislatures, and declaring themselves invested with power to legislate for us in all cases whatsoever.
• He has abdicated Government here, by declaring us out of his Protection and waging War against us.
• He has plundered our seas, ravaged our Coasts, burnt our towns, and destroyed the lives of our people.
• He is at this time transporting large Armies of foreign Mercenaries to compleat the works of death, desolation and tyranny, already begun with circumstances of Cruelty & perfidy scarcely paralleled in the most barbarous ages, and totally unworthy the Head of a civilized nation.
• He has constrained our fellow Citizens taken Captive on the high Seas to bear Arms against their Country, to become the executioners of their friends and Brethren, or to fall themselves by their Hands.
• He has excited domestic insurrections amongst us, and has endeavoured to bring on the inhabitants of our frontiers, the merciless Indian Savages, whose known rule of warfare, is an undistinguished destruction of all ages, sexes and conditions.

In every stage of these Oppressions We have Petitioned for Redress in the most humble terms: Our repeated Petitions have been answered only by repeated injury. A Prince whose character is thus marked by every act which may define a Tyrant, is unfit to be the ruler of a free people.

Nor have We been wanting in attentions to our Brittish brethren. We have warned them from time to time of attempts by their legislature to extend an unwarrantable jurisdiction over us. We have reminded them of the circumstances of our emigration and settlement here. We have appealed to their native justice and magnanimity, and we have conjured them by the ties of our common kindred to disavow these usurpations, which, would inevitably interrupt our connections and correspondence. They too have been deaf to the voice of justice and of consanguinity. We must, therefore, acquiesce in the necessity, which denounces our Separation, and hold them, as we hold the rest of mankind, Enemies in War, in Peace Friends.

We, therefore, the Representatives of the united States of America, in General Congress, Assembled, appealing to the Supreme Judge of the world for the rectitude of our intentions, do, in the Name, and by Authority of the good People of these Colonies, solemnly publish and declare, That these United Colonies are, and of Right ought to be Free and Independent States; that they are Absolved from all Allegiance to the British Crown, and that all political connection between them and the State of Great Britain, is and ought to be totally dissolved; and that as Free and Independent States, they have full Power to levy War, conclude Peace, contract Alliances, establish Commerce, and to do all other Acts and Things which Independent States may of right do. And for the support of this Declaration, with a firm reliance on the protection of divine Providence, we mutually pledge to each other our Lives, our Fortunes and our sacred Honor.

[See the source page for the list of signatories.]

Back in May of 2016, five months after he was sworn in, Mayor Turner announced that former City Council Member and mayoral candidate, Stephen Costello, P.E., would serve as the City of Houston’s Chief Resiliency Officer (CRO).  Mr. Costello’s main objective as the city’s CRO is to make some progress in addressing flooding risks in Houston.

Steve Costello and Mayor Turner. Photo: J. Evans. Reposted from Houstonia.

Since that time Mr. Costello has given out his cell phone number, met with numerous community groups and interested stakeholders. Sources close to his office have indicated that Mayor Turner has approved the appointment of a Flooding and Drainage Task Force who will consider the issues and make recommendations for improving things.  This is consistent with Mayor Turner’s original intent, announced on April 20, 2016.  Here are some ideas the Task Force should consider.

1. Gradually Increase Funding for Drainage System Improvements

Continue retiring our existing infrastructure debt using Rebuild Houston funding. Continue to move to a pay-as-you-go approach. Continue to plan, design, and construct replacements and upgrades to storm sewers to improve service levels. Continue to fix the drainage systems with the lowest level of service first – the so called “worst first.” Gradually increase funding for streets and drainage so that areas with lower levels of service can be addressed.

2. Create Tiered Detention Requirement for Redevelopment

Development in the City of Houston is currently required to provide a volume of detention that is a function of the amount of new impermeable surface area constructed. Under this scheme a 2.0 acre site with no added impermeable surface area must provide 27,150 gallons of detention storage. A 2.0 acre site with 100% added impermeable surface area must provide 325,830 gallons. This reflects the current policy of allowing redevelopment that does not change the runoff volume to not detain very much.

In areas of the city with older public storm sewers that do not meet current design standards, this policy should be adjusted. We should require property owners who are completely reconstructing their facilities to reduce the volume of runoff from their properties to help reduce the burden on these older public systems. This will benefit the private property owner or tenants by reducing the risk of flooding in the vicinity of the property.

This could be implemented using a tiered system based upon the degree to which the site is being reconstructed. For example, if a commercial strip center was repaving their parking lot and updating the center facade and signage, they might have a lower detention requirement than another project that was completely demolishing an existing building and surface parking lot and building a new mid-rise office building with underground parking.

The tiered system might be based on the capital investment per acre or a similar measure of the “degree to which the site is being reconstructed.” The detention requirement would be directly proportional to the capital investment per acre.

3. Define Pervious and Impervious Surfaces More Rigorously

Detention requirements are a function of impervious area, which is intended to account for the volume of stormwater that infiltrates into the ground rather than runoff the site. This seems rational, but we don’t consider how much infiltration any particular surface actually provides. Under the current regulatory scheme ground surfaces with very different infiltration characteristics are lumped into two categories: pervious or impervious. The reality is more nuanced, with different ground surfaces allowing stormwater to infiltrate at various and quantifiable rates. Establishing detention rates using a more nuanced consideration of infiltration rates would be helpful.

4. Create Stormwater Volume Trading Program

Many communities with “one-pipe” sewer systems installed in the late 1800’s or early 1900’s are working to capture, reuse, retain, and detain stormwater volume to reduce the severity and number of combined sewer system overflows (CSOs) under consent decrees signed with the United States Environmental Protection Agency. These communities include Chicago, St. Louis, Portland, Seattle, Philadelphia, New York, Baltimore, Washington DC, and many others (see red dots in the map below).

Cities with populations greater than 50,000 with combined sewer systems. Map from U.S. EPA.

CSOs happen when it rains a lot and the combined system can’t handle the volume of runoff and sanitary wastewater flows. CSOs allow untreated sanitary sewage to be discharged into creeks and rivers.

Every cubic foot of stormwater that can be controlled above ground in a detention basin, a cistern, a green roof, a rain barrel, a bioswale, or some other feature is one less cubic foot that needs to be managed in large, centralized, grey infrastructure facilities – think 40 ft. diameter tunnels. Any storage volume, whether provided by a public entity or a private land owner or developer, helps mitigate the overflow issue.

CSO communities are establishing stormwater volume trading schemes and using the market to create incentives to build “surplus” detention or retention volumes and then allowing the market to sell and purchase these stormwater volume credits.

We should set up this type of stormwater volume trading in Houston to reduce flood risk and flood damages.

5. Use Real-Time Controls

Every hour the Weather Prediction Center of the National Weather Service produces an estimate of the probability of precipitation and the amount of precipitation expected in upcoming 6 and 24-hour time intervals from 1 day to 7 days ahead of time.  These data can now be consumed by stormwater infrastructure control boxes connected to the internet. These real-time weather predictions (which are updated each hour) can now be used to control valves, pumps, gates, and other water system devices to enhance the level of service provided by them. Pumps can be switched on or off, valves can be opened or closed, immediately, based on real time data and decision logic programming.

For example, a cistern could be used for rainwater harvesting to reduce potable water consumption during a period of anticipated moderate to low rainfall, but the same system could be used for detention during a period of anticipated high rainfall.  This is possible by operating our drainage systems using real-time control systems.

We should start deploying these types of systems to help get more from our stormwater infrastructure.

6. Establish Hydrological Basis for Using Green Stormwater Infrastructure

The City’s drainage design criteria imposes a detention requirement that is solely a function of the change in imperviousness from pre-development to post-development. This does not allow the determination of pre-development and post-development hydrology and the direct calculation of the detention volume using a hydrological basis. See this earlier post for an illustration of what this means.

It would be helpful to allow detention volumes to be determined using hydrological principals and calculations and to be derived from the difference between the pre-development and post-development runoff volumes.  This would create more of an incentive to use green stormwater infrastructure (what I call “natural drainage” systems).

7. Try Ground Modifications to Enhance Infiltration

We don’t rely enough on infiltration. We tend to over estimate the volume of infiltration we think we are getting through prairie land (that has been historically farmed). We tend to under estimate the volume of infiltration we think we are getting through our clay soils. We almost always stabilize and compact the soils all over our development sites, which, of course reduces infiltration. Why not create more spongy areas by deep ripping some soils? Why not amend our soils in targeted locations with sand or organic material to enhance infiltration rates? Why not examine soil infiltration rates in our normal pre-design geotechnical investigations?  We could rely more on infiltration to manage stormwater volumes if we actually considered it and measured it.

8. Enhance public education on flooding risks.

We should communicate the risk of flooding more consistently, more effectively, and more loudly. This will help align public expectations with reality. I get the feeling that many people in Houston expect the risk of flooding of anything they own (car, bike, home, etc.) to be nearly zero. I get the feeling that many people in Houston are very disappointed when they find out the risk of car flooding is much, much higher than that. We design new streets to convey stormwater away from homes and businesses. That is worth repeating: our streets are designed to carry stormwater! The storm sewers below our brand new streets are sized so that they can carry a depth of rain that has a 50% chance each year of being exceeded. This means that any particular new street in Houston has a 50% of flooding every year. That occurs when we get about 3 to 4 inches of rain in 24 hours. Better risk communication would not only help our citizens with expectations and management of the impacts of high rain fall, but might help inform a discussion around increased funding for flood risk reduction.