“Do not
free a camel of the burden of his hump; you may be freeing him from being a
camel.” –G. K. Chesterton
A consolidation
of water organizations is taking place in the United States. It is growing more
and more common to see a water or sewer organization (or both) that is taking on
stormwater as the “third leg in the water resources stool.” While there are a
number of organizations that started this way, or assumed stormwater duties long
ago, the trend is now moving to ever-smaller communities. This tendency to
consider water as a resource that just happens to exist interchangeably in the
forms of rain water, drinking water, sewer water, and groundwater (and even sea
water) is a direct result of a number of interrelated drivers,
including
- mixed media regulatory
mandates
- the ability to trade
pollutant credits between wastewater and nonpoint sources
- the growing emphasis in
stormwater management on chemical quality of the
“effluent”
- total maximum daily load
(TMDL) regulatory mandates moving from the planning to the implementation
phase
- the fact that wastewater is
already a utility with a billing mechanism
- the complementary skill sets
involved in managing water-related activities
- the growing scarcity of clean
water in the face of growing demand and potential climate
disruption
Some communities
are beginning to realize that as stormwater is becoming more complex and more
driven by regulations, public works or street maintenance organizations may feel
ill-equipped to make the transition and take on stormwater management duties.
Many public works-type organizations have been successful, of course, but it
takes a concerted, dedicated focus and budget to bring it about. Stormwater as
“other duties as assigned”—in an organization that has other primary duties and
is engaged in stiff competition for general fund revenues—is a recipe for
failure. Such failure could be tolerated before it meant state or federal permit
violations and potential fines, and when citizens were blissfully unaware of
green design concepts. Now, it increasingly cannot.
When casting
about for alternatives, city leaders increasingly come to the realization that
wastewater (and, less commonly, water) organizations may be the right place for
stormwater to land—at least parts of stormwater. There are some advantages to
placing stormwater responsibilities in another water-related utility
organization, mostly revolving around the organization’s mindset to run its
activities as business enterprises under local government or in a regional
setting. (We will not talk about the nefarious practice of “hiding” stormwater
within a wastewater organization to be able to fund it out of wastewater
revenues or through use of an “environmental surcharge.” This is, at best, a
short-term fix that eventually backfires on all involved.)
These
organizations tend to think of themselves terms of
- a municipal
business
- serving
customers
- having a fully funded,
comprehensive program
- operating a well-defined and
owned system
- handling a quantifiable
resource
- meeting strict regulatory
standards as a matter of course
That is very
different from past standard stormwater management practice and has some unique
advantages as we look to the pressures of the future. It has led some wastewater
operators to relish the idea of merging the two types of
programs.
However, in my
experience in helping a number of wastewater entities take on stormwater duties,
there are significant pitfalls, normally realized by wastewater operators only a
year or two into the process of assuming stormwater responsibilities. They may
tend to think that stormwater management is fairly simple, consisting mostly of
getting water to flow downhill and not through homes, and cannot fully
appreciate the subtle and hidden complications. It is like Winston Churchill
commenting on the United States and Great Britain as “two nations separated by a
common language.” Stormwater is expressed in a different
language.
Gaining an
appreciation of these differences can determine whether the development of a
stormwater program is successful or fails to meet community or customer
expectations and regulatory mandates. The changes in how organizations are
structured and how they operate are very significant. I always tell them it is a
bit like those fast-talking ads for some new gizmo—plus about 15 other things
thrown in for free that all seem too good to be true. (“Now what would you
pay?”)
As the quote from
Chesterton at the beginning of this article well illustrates, the trick is to
help a wastewater organization take on stormwater without losing the distinct
advantages and mindset it already possesses. With that in mind, let’s look at
the top 10 things a wastewater manager should consider (but probably would not)
when thinking about taking on stormwater management.
I will group the
considerations into three kinds, with three subheadings for each: 1) flow
related, 2) regulations related, and 3) open-channel related. I will end with
perhaps the most important emerging consideration and begin with the most
important past consideration. (If you’re paying attention, you’ll note that this
adds up to 11 things. As consultants, we always try to exceed expectations!)
Each of these considerations has far-reaching implications for change in the
thinking of the wastewater manager. Many of the potential organizational and
mindset changes toward success are fairly obvious once the specific aspect of
stormwater vis-à-vis wastewater is understood.
Stormwater Is
Intimately Tied to Land Use
For water and
wastewater flows, the system is typically designed with fairly simple objectives
using average flow values and known or assumed peaking factors to obtain the
peak hourly flow rates. The averages are found by reference to population, types
of non-residential development, or numbers of residential units. Often values
are given on a per capita or per employee basis. The sizing of the system is
indirectly tied to land use.
For stormwater,
the sizing of the system and its design characteristics are directly and
uniquely tied to land use and are very complex. It is the accumulated properties
of the land the rainfall encounters that determine the runoff amounts and
properties—other than the properties picked up while the rain is falling through
the atmosphere. Unfortunately, the set of relationships, the various design
standards, and the ability to predict discharges is often a jumble of
conflicting and unknown impacts, data, and standards. And the ability to
influence or control these discharges is equally
undependable.
The stated goal
in modern stormwater design for the leading stormwater programs is, in some way,
to mimic a “predevelopment” hydrologic response. (Though it may be more
appropriate to conceive of a post-development response appropriate to the
changed situation and design to that.) For example, consider Figure
1.
If we are
concerned with trying to mimic the hydrologic response for both large and small
rainfall events, then we must be concerned with at least five integrated design
concepts that exist as points along a continuum:
- Infiltration for the initial amount of
rainfall (dependant on the land cover and soil properties)
- Water-quality treatment for the next
increment, which is the most polluted in terms of concentration (perhaps an inch
of rainfall)
- Erosion reduction for the discharges that
flow between half-bankfull and bankfull and that, for many stream types, do the
most “work” on an annual basis in moving sediment (1-year to 5-year
storms)
- Flood-control criteria for those
near-bank-overflowing discharges (5-year through 25-year storms), which, if they
caused damage, would result in high average annual costs to
citizens
- Those more rare discharges that comprise
the design or regulatory floodplain (normally the 100-year storm past, present,
or future)
Each of these
design criteria is related to the land use, drainage patterns, soil conditions,
and antecedent weather. And every larger storm contains, nested within it, the
impacts of the smaller to some extent. This is far more difficult than water or
wastewater sizing and, like most things about stormwater, far less
exacting.
Because
stormwater is so connected to the use and modification of the land over time,
the stormwater manager must have a strong and even regulatory voice in how the
land is used and how others are allowed to impact the public stormwater system.
In many places this does not happen or is outside (upstream of) the political
control of the entity.
And to further
complicate things, much of the stormwater system was “sized” by nature over
hundreds or thousands of years, and the current “natural” stream channel may be
neither natural nor stable. A general shift may be ongoing, undetected by the
casual observer. For example, in the North Carolina Piedmont, streams that had
been choked with sediment since the land was first cleared are now downcutting
to—or beyond—their original level. What should the design be in that case? What
is natural?
Is there a
parallel with wastewater? For example, under what conditions can a developing
parcel of land be allowed to “connect to” or “tap into” the public stormwater
system? Is that concept even valid for stormwater? Is there a public system? Who
controls it? How much control can—or should—a wastewater manager exert over
zoning changes or zoning standards?
But wait, there’s
more!
Flow-Related
Considerations
Stormwater
Is a Provisional System. In
contrast to other municipal systems (water supply, wastewater treatment, roads,
solid waste) that are highly visible and/or provide a service that is used
regularly and directly by citizens, most stormwater systems are on “inactive
status” a majority of the time. Any existing problems are often invisible to the
public and therefore ignored. Stormwater systems work flawlessly when it is not
raining. Heavy rainfalls such as a hurricane or violent thunderstorm are
relatively rare, and much of the installed capacity of the stormwater system is
therefore “provisional” in nature because it is designed for rare storm events.
However, when circumstances demand, proper function of the stormwater system
becomes essential to community health and the safety of people and property.
Unfortunately, proper function of the various components of the stormwater
system is evidenced by a lack of problems (flooding, pollution, traffic
disruptions, etc.), whereas improper function is all too readily
apparent.
This is very
different from wastewater or water supply, wherein an improperly functioning
system is almost immediately felt and often promptly fixed. A burst sewer main
is immediately fixed, day or night. But a clogged channel may go for years
without attention.
In addition,
there are very few ways to tell when a system is not properly functioning. Yes,
a simple inspection can tell if the system is clean and clear, but it cannot
tell if it is undersized. And even if a flood occurs, it is difficult to know if
the flood was a 10-year flood, a 25-year flood, etc. because there is little
direct data. When we move beyond flooding to water quality and other aspects of
the provisional system, the complexities increase.
Management of
such a system invariably means a trade-off between known and experienced
problems and problems that only show up because a model says the system is not
adequate. The older and smaller the system, the higher the probability that it
has been tested by storms at or above the design capacity. In these cases,
having good rainfall data supplemented by NEXRAD will help the manager assess
whether the system is in need of rehabilitation. But in most cases, for the
stormwater program to be successful, it cannot be driven by reports of failure,
but must be paced through inspection and remediation—through the setting and
enforcing of levels of service that can be measured in the field regardless of
the storm event. For new designs, the standards must be technically sound,
thorough, and enforced.
Stormwater
Has Unlimited Peak Flow. If
Noah floats by, we will all be underwater. That is, there is a diminishing but
real probability of an ever-larger flood peak. While the absolute peak flow
within a water or wastewater system is fairly easy to predict and is cyclical in
nature (or episodic, like the end of the last American
Idol episode!), stormwater is
flashy, rare, and extreme. In wastewater and water supply, there is a design
approach that normally allows for the plant or system to handle all peak flows
within its planned capacity. Rarely, if ever, is the system capacity exceeded
with the resultant sanitary sewer overflow or water shortage. If these other two
systems experienced such problems on an annual basis, they would be subject to
both public and legal proscription.
However, with
stormwater, the story is very different, even for a perfectly designed and
maintained system. In a sense, we design these systems to fail. A thought experiment will
tell the tale. Consider the following five points:
- Each part of the stormwater system is
designed to handle a specific discharge—say, the 10-year storm. So what we are
saying is that by
design we intend for this
particular part of the system to fail, in some way, one year in 10—or to have a
10% probability of failure every
year.
- There is not just one culvert in our town
but thousands of culverts and inlets and other system components, all designed
for this 10-year storm (or some other return period), and a growing number of
low-impact development (LID) components whose performance in the face of larger
storms is not yet fully understood.
- Rainfall depths used in our design are
point values, not areal values. That is, every point
of land within our jurisdiction must, on average, experience a storm that
exceeds our design storm one year in 10.
- For most of the country, the normal type
of storm that floods small urban areas is a thunderstorm, which has an average
diameter anywhere from a city block to a couple miles. You can have a flood
problem in one parking lot and not in the adjacent one.
- Few design criteria require the designer
to consider what happens to the flow when the design storm is
exceeded.
Now let’s put
these facts together and we will see that stormwater is vastly different from
wastewater or drinking water. What these facts point to is that, by
design, we are planning to have
many potentially damaging flood events in a local jurisdiction every year. And
this is true even if the whole system is designed appropriately and maintained
to perfection. A larger community should plan for many 100-year storms in a
single year (of small areal extent) in order to have each blade of grass
experience such a storm once in a hundred years. It is a risk-based analysis
with a very high probability of failure.
The implications
of how stormwater is managed include having an ability to respond to
emergencies, to gather detailed rainfall data, to practice safe stormwater
design by actually looking at non-damaging overflow points, and to have known
and static floodplains if we want to promote flood safety. But it can be a
public relations nightmare, especially given the next
consideration.
Based
on Land Ownership Not System Ownership. Can you imagine the scenario where a wastewater
operator receives a complaint that a sewer pipe is broken and leaking and
responds, “Sorry, it is not in the right of way; we don’t respond to those kinds
of complaints”? That would be unthinkable in the utility paradigm wherein
ownership of the system, not ownership of the land underlying the system, is
key. But in stormwater that happens all the time. Should
it?
Consider the
typical case for the small to medium Midwestern town in a typical neighborhood
as shown in Figure 2. The city manager has just decided that the wastewater
department should take over the stormwater function. This “system” is then
handed to the wastewater operator (along with only the best of public works’
equipment). The wastewater operator goes out to take a look at a drainage
complaint and finds a mishmash of ditches, pipes, driveway culverts, ephemeral
and perennial streams, ponds, inlets, and other miscellaneous structures. There
are few easements, and he or she finds that it is street water that is causing
the flooding or erosion in someone’s backyard. About that time, “water running
downhill” is the least of the worries.
Unlike in the
wastewater system, there are no easy answers to questions such
as
- What defines the limits of
the public system, and who owns it now?
- What is the city’s legal and
moral responsibility?
- What is the city’s risk if it
begins to try to operate the system?
- What is the city’s
responsibility for individual pollution generation?
- What are the appropriate
steps and timeline to bring about change?
Unlike the
wastewater system, the stormwater system retains a legacy of blurred lines of
ownership and responsibility. In many places, it would be considered “illegal”
for the county or city to move off of the public right of way to “improve
private property.” No such legal conundrum faces the wastewater operator with
respect to the sewer system. Things in that world are more defined and
set.
Most local
governments own a system of streets, roads, and bridges, which are constructed,
owned, and operated for the public’s benefit. For example, the express power to
grade and open streets implicitly carries with it the power of local governments
to establish a storm drainage system. This power, however, does not include the
right to redirect surface waters onto adjacent private properties to the
landowners’ detriment. The owners may sue the government for damages in such
situations. Therefore, the duty on the local government is twofold. It must
adequately design and construct its drainage system so as not to divert water
onto private property in quantities more than its natural flow and cause damage,
and thereafter it must maintain the drainage system so that its operation does
not constitute a nuisance. Many states are developing a body of case law
indicating that if public water (i.e., street runoff) causes a problem, the
local government is most often found to be liable for
damages.
In the face of
this legal backdrop, many wastewater operators face the following situation. The
past stormwater systems and programs have not effectively prevented or corrected
flooding problems, controlled the discharge of pollution in stormwater, or
relieved impacts on other municipal facilities, such as roads and wastewater
collection and treatment works. In older neighborhoods, like the one shown in
Figure 2, the drainage systems were built to outmoded standards. Long stretches
of streets have no inlets along the curb lines but simple breaks into yards.
Stormwater pollution control was not even imagined when the neighborhood was
built. Many ditches, storm sewers, and detention structures are nearing (or have
exceeded) their useful lives and/or have insufficient capacity. Large segments
of the drainage system are not presently under active management, most notably
creeks and ditches where few easements or rights of entry exist for maintenance
access. Deferred maintenance of parts of the drainage system that are
inaccessible has accelerated the deterioration and compromised their
functionality, increasing the frequency of flooding. And the city manager wants
the wastewater operator to add a “flat fee” to the wastewater charge in order to
solve these problems and meet the growing demands of the regulatory
program.
The shift from
operating a wastewater system—where the system is used everyday with generally
known and limited peak flows and legal and defined access—to operating a
stormwater system—where the system lies unused most of the time, where the
demands can be violent and unexpected, and where the operator cannot access much
of the system to solve problems—demands clear education, detailed understanding,
and a strong plan of action, along with stable and adequate funding not tied to
wastewater flows.
All this for only
$3.25 a month. But wait—if you act now…
Regulations-Related
Considerations
Stormwater
Is Based on “Maximum Extent Practicable.” On December 8, 1999, the EPA modified parts of
Title 40 of the Code of Federal Regulations to include stormwater discharges
under the National Pollutant Discharge Elimination System (NPDES) program, and
stated in the preamble to its implementation of the Water Quality Act that
NPDES
permits for discharges from MS4s (1) may be issued on a system or
jurisdiction-wide basis, (2) must include a requirement to effectively prohibit
non-storm water discharges into the storm sewers, and (3) must require controls
to reduce pollutant discharges to the maximum extent practicable, including best
management practices, and other provisions as the Administrator or the States
determine to be appropriate for the control of such pollutants. At this time,
EPA determines that water quality-based controls, implemented through the
iterative processes described today, are appropriate for the control of such
pollutants and will result in reasonable further progress towards attainment of
water quality standards.
On that date,
stormwater became a strange bedfellow with wastewater, partnering in the set of
standards and rules designed to reduce and eliminate the discharge of pollutants
to waters of the United States. But stormwater is only a marginally like
wastewater in both approach and measures of compliance.
With wastewater,
numeric effluent quality is the goal. How that quality is attained is of little
concern to regulators in most cases. If a biological-oxygen-demand exorcist was
able to cast the pollution out of the effluent to the attainment of standards,
that would be sufficient. What we attain matters most.
With stormwater,
because at this point in time there are few places that have numeric stormwater
wet-weather standards, what
we do becomes the measure of
compliance and only indirectly what we attain. It is all about the definition
and negotiated activities contained within the term “maximum extent
practicable,” or MEP. If you do what you say you will do, then you are, by
definition, in compliance with your permit. Measurement of stream health serves
to guide the “iterative process” mentioned above, steering inexorably toward
clean water.
Unlike
wastewater, where the “cause and effect” has been well worked out, in stormwater
things are still very much in the “experiment and see” stage—though great
progress is being made. If we are lucky, we will have numeric effluent
limits by 2013 as envisioned by the permit writers.
Stormwater
Is Characterized by Episodic Discharges of Nonpoint-Source
Pollution. Part of the problem with stormwater is that it is a
series of thousands of nonpoint sources with point delivery mechanisms. Every
plot of ground, every citizen, every activity can become a source of
pollution—and little of it is contained within any kind of controllable system.
In addition to that, the actual impact of the pollutants on the environmental
system is ill understood in aggregate. Data are often scarce because of the
transient wet-weather nature of it all. We often are reduced to seeing the
aftereffects of storms or the accumulation of more subtle impacts on a stream or
other receiving water systems and trying to deduce what caused what.
This is different from wastewater, where things are
contained, have point sources, are understood, and happen everyday in generally
predictable ways. There are limited entry points to the closed system, and these
can be better controlled. And, there is the ultimate stopper: the treatment
plant.
Stormwater
Has No Ultimate End-of-Pipe Treatment. Early in the consideration
of the treatment of stormwater for pollution, knowing wastewater engineers began
to lay out and price immense stormwater treatment plants. This led to some
equally immense costs and even larger shouts of protest against the “fact” that
requiring local governments to actually treat stormwater would bankrupt the
nation. In the end, it was the other end of the pipe that got all the
attention.
Stormwater quality is like a sanitary pretreatment
program on steroids. While we tend to treat stormwater flooding through the use
of detention ponds (newer LID concepts notwithstanding), we need to treat the
quality portions of stormwater as near to the source as we can get, or we would
end up sacrificing portions of the stormwater system we are trying to preserve
(unlike wastewater, where “pipe preservation in its natural state” is an
absurdity). In fact, the most upstream point in the watershed is probably
Bubba’s brain (or Kip’s and Ashley’s brains). If we can keep pollutants from
getting into the stormwater system in the first place (being plumbed, dumped, or
washed in), then we do not have to work so hard to remove them. So if we can
change the runoff footprint of land use, change regulations, and conduct
effective public education, the battle is half over. The other half of the
battle is how to actually treat runoff.
As shown in Figure 3, this has led to multiple
parallel and cascading stormwater treatment concepts (the “treatment train”)—few
of which are at the end of the system. We begin in the minds of the average
citizen with education and further “downstream” with ordinances, signage, and
enforcement. We then attempt to layout sites using green design concepts so that
they do not generate so much pollution, and so the pollution that is generated
is filtered through green areas. Farther downstream, we look at smaller
dispersed treatment devices that look for all the world like small wastewater
treatment plants: rapid sand filtration, vortex concentrators, skimmers and oil
separators, screens, and settling devices. (But we call them things like “rain
garden” and “buffer area” and “infiltration area,” reflecting the fact that it
was wastewater treatment that mimicked natural processes in the first place.)
The problem is, of course, that we do not own any of these things and they,
unlike wastewater systems, are subject to the vagaries of private
maintenance—somewhat similar to an onsite wastewater treatment (septic) program.
Further downstream, we may have larger treatment devices that do double duty for
flood control (ponds, wetlands), and in the end we promote in-stream approaches
that enhance bank stability and habitat.
The management implications of this unfamiliar
regulatory environment include strong emphasis on public education and
involvement, the need to inspect and enforce compliance of systems on private
property, the need for local monitoring of actual improvements in stream
quality, and the need to intersect the land development process in effective
ways. None of these approaches is within the daily experience of most wastewater
operators. In stormwater management, we must be content to do what we can in
these arenas, monitor effectively during wet weather, trend in the right
direction, and make incremental changes—facing new iterations of the stormwater
NPDES permit as we go; building on this firm foundation, we are looking ahead
eagerly to a more full-bodied implementation of the TMDL program.
Now what would you pay? But wait, there’s even
more!
Open-Channel-Related
Considerations
Mobile
Boundary Open to the Air.
Perhaps the strangest thing about stormwater, from the wastewater operator’s
standpoint, is the fact that much of the system is defined by a series of
ditches and streams—not pipes. The skills and approaches to managing such a
system, when compared to a piped system, are different in significant but subtle
ways.
For example, the
implications of dealing with a non-fixed boundary come into play. In many
places, this is not just about bank erosion but also about understanding the
sediment transport that is necessary to keep the stream in balance (in regime).
It also means that the system can overflow at any point along the system, but
with the simplifying fact that the water will also run back in the way it came
in. And in most instances, it will not run along streets and go places it does
not belong—as is the case when sewage emerges from
manholes.
As mentioned,
much of the stormwater system has been “sized” by nature over hundreds or
thousands of years, and the current “natural” stream channel may be neither
natural nor stable. In the case of the North Carolina Piedmont, streams that
have been choked with sediment and are now downcutting to, or beyond, their
original level. Ancient tree stumps are emerging. What should the design be in
this case? What is natural? What is correct in light of the changing baselines?
Can we have a natural stream in a changing urban setting—or should our target be
different from that?
Because the
system interacts with nature in ways that either mimic stream flow or are stream
flow, this concept also means that nature can intrude into the system, and even
that nature may rule what can be done with the system itself. The conveyance
needs of the wastewater operator may come in a distant second, or
third.
Ecology
and Habitat Are Key. Our
goal in a sanitary system is to have plenty of mesophilic bacteria to “digest”
the effluent. The only habitat we are interested in creating is one in which
this is maximized either aerobically or anaerobically. When we discharge our
effluent, we are interested in habitat and ecological health—but our normal
motivation is compliance only. (Although I did recently hear of a treatment
plant that was experimenting in the use of tilapia in its tanks to eat slime and
to be eaten in return if toxicity tests are favorable.) With drinking water, the
goal is to totally eliminate all organisms except of the human kind from contact
with the water. The “habitat” we are interested in is sterile and clean—and we
ensure this is the case with chlorine.
Contrary to these
systems, in stormwater open-channel systems, the goal in ever-increasing ways is
to try to maintain a natural habitat to ensure the survival and propagation of
all manner of organisms, from the lower niches of the food web to the upper.
Biocriteria are used to measure stream health. Buffers are sized using habitat
as a strong consideration. Shade, natural vegetation, large woody debris,
in-stream structures, substrate quality, and other factors are all of
concern.
Much of what the
manager does has to do with recognition, restoration, and preservation of
natural habitat. This requires the wastewater—now stormwater—operator to balance
many, often competing, interests, interest groups, and regulatory mandates in
ways that would be unusual in the world of wastewater treatment except where
encounters with the Endangered Species Act have already limited sewer expansion.
For example, to modify a channel to improve the conveyance means working through
a maze of permit requirements, studies, and designs to demonstrate that there
will be no harm to the environment of the stream itself. It becomes a balancing
act between flooded homeowners demanding protection, and a beautiful but
“undersized” stream.
People
Can Interact With and Enjoy the Flow. And now to the part that may be most foreign to
a wastewater manager.
In wastewater
treatment organizations, as well as in drinking water organizations, the primary
human interaction is in establishment of accounts and payment of bills. There
may be a strong water conservation outreach component, and there may be a
general branding of the organization. But in most cases this is a sidelight, not
the main event. People tend to avoid all things sewage, and the last thing they
want is to be located next to a treatment plant or even a buried
interceptor.
Stormwater can be totally different—especially when it
comes to well-planned and well-administered streamside land use. People actually
flock to and enjoy interaction with the stream conveyance system. In many
cities, this system is a centerpiece of a neighborhood and a strong economic
driver (take for example San Antonio, TX, where a converted flood-control
channel drives the economy). Studies have shown that people prefer clean,
flowing water over any other kind of passive recreational setting. Greenway and
riverfront systems in urban settings create centerpieces for community
involvement and recreation. Denver’s interaction with Cherry Creek and the
riverfront and Chattanooga’s aquarium complex are prime examples.
Thus, while the
wastewater operator provides an expected and necessary service, hidden and
functional, the stormwater manager can be in the position to provide a
near-priceless and singular amenity important to the life and vitality of the
community. This opportunity does not come without pressures political,
environmental, and economic.
Ready to buy
yet?
Stormwater Is the
Only Input to the Hydrologic Cycle
Public works and
city engineers are used to the understanding that stormwater is to be cleaned
and conveyed to a receiving water safely being escorted to the downstream
boundary of the community and released. There is a collective sigh of relief
when a large storm does no damage, and benign neglect at other times. That is
changing radically.
There is one last
major difference between stormwater management and wastewater/drinking water
management that bears discussion. While these latter two water utilities are
users of water, the stormwater manager is the supplier of it—well, maybe works
with the supplier of it. In any case, this is a very
important distinction. In the West, stormwater managers are mostly an adjunct to
water suppliers and flood-control districts. In the East, water and sewer are
king, with stormwater as the
redheaded stepchild coming late to the table. However, stormwater runoff is
rapidly shifting, even in the East, from a common enemy to be protected against
to an invaluable commodity and resource to be planned for and conserved.
Recently, some communities in the East were in fear of running out of drinking
water. Reservoirs were at an all-time low. An on-ground water pipe was strung
between cities to try to ensure shared dwindling resources. Governors prayed
publicly for rain.
Operators of
wastewater and water utilities are in a unique position in this framework of
scarcity. They are used to dealing with clean water and even effluent as a
measurable resource to be handled in specific ways: treated, recycled, reused,
injected, stored, and conserved. It would be second nature to consider
stormwater in a similar fashion—a measurable commodity to be handled within the
urban setting as part of the overall water resources picture, one in which
effluent, runoff, and clean water are managed in a complimentary fashion to
maximize our water resources.
Thus, this shift
to combined water utilities, for whatever reason, is welcomed as the country
seems to be moving into a period of dwindling water supplies (whether cyclical
or a result of human-induced climate change) and growing water demands. The
combination of water, wastewater, and stormwater into a seamless whole will
increasingly create vital synergies in the future—reducing redundancy and
creating opportunities to maximize water use and multiplied appropriate reuse.
There are many examples of this being done successfully. In the East, the
Louisville and Jefferson County Metropolitan Sewer District, the Philadelphia
Water Department, and Nashville-Davidson County Metro Water are some good
examples. In the West, Denver and Seattle come to mind. I’m sure there are many
others who serve as good examples.
But water and
wastewater operators should not underestimate the complexities of stormwater
management.
It does much more
than simply run downhill.
Pick up the phone
now and call this number!