Introduction

South Bass Island, Ohio, in Lake Erie, is home to 900 residents and hosts more than 500,000 visitors each year. On August 2, 2004, the Ottawa County Health Department received calls from persons experiencing gastroenteritis after visiting the island. By September 4, approximately 1,450 cases were reported by residents and visitors (O’Reilly et al. 2007). An analysis of the hydrodynamics of the island and Lake Erie identified likely links among island waste disposal systems, the lake, and island groundwater (Fong et al. 2007). On the island, a public water system served the community of Put-in-Bay, but many businesses and residents used untreated groundwater pumped from private wells for potable water. Sewage disposal on the island consisted of Put-in-Bay’s publically owned treatment works and residents’ on-site wastewater treatment systems, including septic tanks. Heavy rainstorms during May, June, and July 2004 transported contaminants from sewage discharges to the lake and from wastewater treatment facilities and septic tanks to the subsurface water and possibly raised the island’s water table. In addition, Lake Erie experienced strong currents in July. All of these issues may have been factors in an extensive surface water–groundwater interchange that contaminated the island’s potable-water supply. In response to the outbreak, the Ohio Environmental Protection Agency and the Ohio Department of Health planned to protect public health in the future by supplying the entire island with treated drinking water from Lake Erie and by planning for an islandwide sewer system (Fong et al. 2007). These cross-contamination events are likely not unique to South Bass Island and suggest critical vulnerabilities for other communities.

Providing safe water is perhaps the most ancient challenge of built environments. Water is necessary for life, and even early civilizations used precious time and resources to ensure a sufficient water supply for growing communities. However, water also brought significant public health challenges, including waterborne diseases and long-term consequences from using water for waste disposal.

In developed countries, water and sanitation issues were “solved” a century ago (Melosi 2000), and now most people take water for granted. We drive across our cities, barely aware of the streams we cross or the watersheds they define (Figure 6.1). We build extensive suburbs with thirsty lawns, ignoring the consequences of using that much water. We build extensive impervious surfaces (Figure 6.2), unaware that they are changing runoff dynamics.

Figure 6.1
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Water flows through the hydrological cycle, contaminated at some stages by road runoff, agricultural uses, and sewage, and cleansed in other stages by water and wastewater treatment plants, ground filtration, and evaporation (Frumkin, Frank, and Jackson 2004).

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Figure 6.2
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As investigated in this demonstration at Iowa State University, pervious concrete (on the right) handles stormwater runoff, urban heat island, safety, and freezing issues better than impervious types of pavement (on the left) (photo: John T. Kevern).

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The built environment interacts with the baseline supply of water (think of Las Vegas and Phoenix), people’s behavioral choices, and the weather to affect the quality and quantity of water available. This chapter provides a short primer about potable water and wastewater in the United States. It then addresses three challenges: too little water, too much water, and water quality. In each case the built environment can aggravate or ameliorate the challenge, from the small scale of homes and yards to the larger scale of regional water conveyance systems. This chapter also considers water infrastructure issues in developing countries and policy interventions.

Water Primer

Drinking Water

In the United States, the primary sources of household drinking water are municipal drinking-water systems (≈ 87 percent of households), private wells serving one to five units (≈ 12 percent of households), and other sources (≈ 0.7 percent of households) (US Census Bureau 2007). Alternate sources of household water include cisterns to capture rainwater runoff from roofs, such as those used in Hawaii (Hawaiian Island Homes Ltd. 2010), and water hauled from local springs and livestock wells, which occurs in some rural areas of the Southwest (deLemos et al. 2009).

Mandated protection of drinking-water quality is limited to public water systems (PWSs) covered by the federal Safe Drinking Water Act, administered in part by the US Environmental Protection Agency (US EPA), and a patchwork of state-based programs. The US EPA (2010) defines PWSs as entities providing water through pipes or other conveyances to at least twenty-five people or fifteen service connections for at least sixty days per year. PWSs are required to test the water they provide to their customers for a list of microbial, chemical, and radiological contaminants. The concentrations of these contaminants are limited to prescribed levels, called maximum contaminant levels (US EPA 2009b).

For non-PWSs, such as private wells, some states have enacted legislation to ensure that this water also meets a minimum standard. For example, New Jersey’s Private Well Testing Act mandates testing of untreated groundwater for thirty-two parameters of human health significance, such as concentrations of total coliform bacteria and of mercury, before transferring property that includes a private well (Atherholt et al. 2009). In contrast, the Florida Department of Health, Division of Environmental Health (2009) provides recommendations and information but does not require private well testing.

Although there are state programs to protect well water, requirements are typically restricted to microbial contaminants and nitrate concentrations. Unless there is a known or suspected problem with the well or water, many home-owners do not conduct periodic testing and other recommended maintenance. As nearby land-use and local weather patterns change, the quality of water in private wells may be adversely affected by surface waters, contaminant plumes, and saltwater incursion. In addition to the effects on water quality, an increase in the number of users withdrawing water from an aquifer or an increase in withdrawals by a single user could surpass well capacity. In the absence of periodic testing data, baseline values and trends in the quantity and quality of much private well water are unknown.

Based on the mandated level of drinking-water protection, requirements for the supporting built environment vary. A PWS requires substantial capital investment in infrastructure (storage areas, pipes, valves, pumping stations, water-quality testing laboratories) and ongoing support from customer revenues. A PWS allows the construction of dense cities with mingled offices and private homes all drawing from one large water resource. Installing a private well requires capital as well; however, the footprint is much smaller than that of a PWS and requires less supporting infrastructure. In addition, using private wells limits the household density possible in a given area, which has implications for other infrastructure such as roads, public transit, schools, and retail stores.

Wastewater

In the United States, the primary sewage disposal methods are public sewers (≈ 79 percent of households), septic tanks, cesspools, or chemical toilets (≈ 20 percent of households), and other means (< 1 percent of households) (US Census Bureau 2007). Public sewer systems collect and transport sewage directly to a publicly owned treatment utility. Severe weather, improper system operation or maintenance, and vandalism can result in unintentional discharges of raw (untreated) sewage. Untreated sewage from these overflows can contaminate local waters, including drinking-water sources, and threaten public health. The US EPA (2009c) estimates there are at least 40,000 sewage system overflows (SSOs) each year.

Another public and environmental health threat from public sewer systems is the combined sewer overflow (CSO). In 772 US cities, sanitary sewer systems connect to storm sewers intended to carry precipitation runoff away from urban landscapes (US EPA 2009a). During heavy rainfall or periods of rapid snow melting, water captured by storm drains combines with wastewater, overwhelming the local sewage treatment system. The CSO then discharges untreated human and industrial wastewater directly into nearby water bodies (US EPA 2009a).

As with private wells, small on-site wastewater treatment systems (OWTSs) such as septic tanks present both the opportunity to develop land without an extensive infrastructure investment and the obligation to allow enough land per household to disperse wastewater. Although septic system use occurs primarily in rural areas with limited or no access to sewers, some urban and suburban areas with little sewer access have historically relied on septic systems to support growth. However, water piped to a household with an OWTS is effectively lost from the local water system because it is likely to return to the original water basin long after it would have naturally. Thus, serving densely populated areas with such on-site systems has significant consequences for downstream water management, particularly during droughts.

Using septic systems to support suburban expansion risks generating other long-term costs, such as those associated with retrofitting entire neighborhoods with sewer systems once septic leach fields become saturated. On a smaller scale, OWTSs pose a cross-contamination risk for nearby private wells. When an OWTS fails, it releases partially treated wastewater containing human pathogens and chemical contaminants into the local environment.

This brief discussion of basic components indicates how water conveyance infrastructure is an integral part of the built environment. The next sections describe how water quantity and quality may affect decisions about constructing the built environment.

Water Quantity

Too Little Water

An imbalance between supply and demand forces many communities to face periodic or chronic water shortages. One of the long-term challenges is regional evolution in climate resulting in permanent decreases in available rainfall. For example, increased desertification in parts of Australia and the southwestern United States has placed modern cities, such as Sydney, and geographically remote tribal lands at risk for severe, permanent water shortages. Another challenge is seasonal variation in rainfall that results in prolonged droughts alternating with extreme precipitation events.

In developed countries, highly concentrated and growing populations can easily outstrip local water resources. Larger homes with greater water demands and thirsty urban landscapes, such as lawns, increase the per capita demand. Sprawling development increases the geographical area served by PWSs, and distributing drinking water over large distances is inefficient. For example, in the United States an estimated one trillion gallons of water are lost each year to broken pipes and infrastructure damage (US EPA 2011). Finally, local planning decisions, such as Las Vegas’s long-term overuse of water resources to irrigate expansive landscapes, may ultimately make some potentially livable spaces, such as desert cities, unsustainable. Whether the reason for water shortages is local development, regional weather patterns, or population growth outpacing available resources, water resource preservation should be a high priority in community design decisions.

The best response to water scarcity is to limit its use. Individual efforts contribute substantially to reducing community water use. Smaller homes surrounded by xeriscapes can reduce or eliminate the need for supplemental irrigation. Some household activities, such as flushing toilets and washing clothes, typically use more water than is needed; existing toilets and appliances can be replaced with more efficient models. On a larger scale, surrounding dense population centers with natural settings, including woodlands and wetlands, and including more areas with pervious surfaces within population centers are choices that retain rainwater and provide wastewater filtration.

Water reuse is another important component of efforts to preserve water resources. In most places, treated wastewater discharges into nearby water bodies. Although the receiving waters may be used as a drinking-water source downstream of this discharge, wastewater treatment and discharge and drinking-water intake and treatment are typically independent linear systems; that is, wastewater is not captured directly and retreated for potable use. Alternate approaches to water use can limit the unidirectional flow of clean potable water into increasingly contaminated discharges to the environment.

On a very small scale, gray water, the water left after household uses such as washing dishes or bathing, can irrigate landscapes, thus reducing the total amount of treated water needed. Water reuse can be scaled up to regional planning zones that recycle water for large geographical areas. Although water reuse may be technically feasible, it may not be economically or socially acceptable.

One of the best examples of socially acceptable wastewater recycling occurs in the island nation of Singapore, which has limited and diminishing water resources (PUB 2008). Drinking-water sources include rainwater and raw water imported from Malaysia. In 1998, the Public Utilities Board and the Ministry of the Environment and Water Resources initiated the Singapore Water Reclamation Study (NEWater) project. NEWater is wastewater treated using microfiltration, reverse osmosis, and ultraviolet technologies (Tigno 2008). In a process called planned indirect potable reuse, the utility blends NEWater with reservoir water in preparation for conventional potable-water treatment. As part of the reclamation project, the utility conducted a public relations campaign (From Sewage to Safe) and NEWater was expected to make up at least 2 percent of Singapore’s total daily potable-water consumption in the near future (Figure 6.3).

Figure 6.3
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Suitable for drinking, this bottle of NEWater is produced in Singapore from purified wastewater (photo: Lorraine Backer).

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Too Much Water

Having ample water generally means better health (Cairncross 1997); however, the unexpected presence of too much water presents other challenges for the built environment. Flooding associated with natural disasters can severely affect both coastal and inland communities. In 2005, the storm surges resulting from Hurricane Katrina and the subsequent flooding caused $125 billion in damage to coastal cities, including the water conveyance infrastructure (“Katrina Damage Estimate Hits $125B” 2005). The disaster also created an extensive refugee population that challenged the economic and physical infrastructure of many inland communities. In 1993, a Mississippi River flood severely affected the midwestern United States. Floodwaters inundated many PWSs and private wells, increasing the risk of human exposure to waterborne pathogens and chemical contaminants (CDC 2008).

Decisions about land use and the local built environment can exacerbate public health impacts from too much water. Many US cities already face problems with sewer and storm water discharge associated with old pipes and growing populations. One of the predicted consequences of global climate change is regional increases in the frequency of heavy rain events. Many water-borne disease outbreaks are preceded by extreme rain events (Curriero et al. 2001). Replacing wastewater infrastructure may be economically infeasible, and municipalities are turning to other creative ways to minimize storm water runoff and improve water quality. Capturing runoff in rain barrels and roof gardens and using swales (Plate 4) slows water flows and reduces the amount of sediment and other contaminants that flow into local waterways.

A number of cities have successfully used rain gardens to help manage stormwater runoff. For example, Muncie, Indiana, used a federal environmental health grant (CDC 2009) to investigate the effectiveness of rain gardens in reducing environmental health risks from surface water runoff. The Muncie Bureau of Water Quality conducted a water-quality assessment, developed community partnerships, created educational materials, distributed nine hundred rain barrels to community members, and created five demonstration rain gardens. Originally, there was considerable community skepticism and complaints about ugly barrels and “weed patches”; however, the team enhanced acceptability by demonstrating rapid improvements in local water quality resulting from slowing storm water flow.

In 2005, Kansas City, Missouri, launched the 10,000 Rain Gardens initiative to encourage a community-wide effort to address storm water runoff—the major regional water pollution problem (10,000 Rain Gardens 2010). The launch included extensive advertising urging citizens, corporations, and nonprofit organizations to join local governments to tackle the storm water and regional overflow issues. The program also offered training for professional landscapers. The campaign resulted in a double-digit increase in awareness that storm water was Kansas City’s leading source of nonpoint-source pollution—and more than 300 rain gardens in backyards and corporate landscapes.

As the amount of pavement per unit area increases, more precipitation runoff flows to urban streams and other catchments. For some cities, storm water runoff occurs on a much larger scale than individual rain barrels or community rain gardens can accommodate. Unless cities are diligent in monitoring changes in runoff water flow and making needed repairs and amendments to storm water conveyance systems, they may suffer extreme consequences, even from normal precipitation events.

The 2009 flood in Atlanta (“Runaway Runoff” 2010; “Tide of Resistance Rising over Runoff” 2010) illustrates the importance of building and maintaining appropriate storm water management infrastructure in a metropolitan area. From 2000 to 2010, the population of the greater metropolitan Atlanta area increased by almost 150,000 people annually (Atlanta Convention & Visitors Bureau 2010), reaching nearly 5.5 million people by decade’s end (“Atlanta Moves to 9th Largest US Metro Area” 2010). During this time of explosive growth, many developers ignored requirements to build storm water controls, and limited city resources precluded maintaining existing infrastructure. Even unremarkable rainfalls led to dangerous flash floods that damaged personal property as well as the city’s sewers and storm drains. Added to this was the failure to update historical flood demarcations (for example, the predicted extent of a 100-year or a 500-year flood) and to obtain necessary storm water permits for the city’s highways. During September 2009, Atlanta experienced a storm and subsequent flooding that exceeded all predictions based on historical data, and even many areas not located in a designated flood plain were under water. Homeowners were stranded—literally in flooded homes and economically when they learned they did not have insurance coverage.

Other land-use decisions may put coastal communities in harm’s way. Coastlines and barrier islands are evanescent land features. Extensive development of coastal areas and barrier islands stresses freshwater resources. When coastal communities pump groundwater more quickly than local recharging sources can replace it, salt water intrudes into the aquifer. Removing naturally occurring coastal vegetation, such as mangrove forests, to provide coastline access, develop recreation areas, and enhance local aquaculture puts coastal and inland communities at risk from storm surges and other severe weather-related damage previously mitigated by the forests. Limiting development on fragile coastlines and barrier islands would limit the public health risks and costs of replacement when disasters occur.

Island nations are particularly at risk from too much water. In the Bahamas, poor local coastal zone management has led to infrastructure failure that has enhanced rather than prevented shoreline retreat (Sealey 2006). Storms periodically washed away coastal roads, and many cities responded by repairing old hard structures or building new seawalls. Storms damaged many of these hard structures because they were improperly constructed or poorly located. By contrast, along other parts of the coastline, “soft” approaches such as beach nourishing (adding sand along the water’s edge) and sand dune regeneration have succeeded in protecting both the shoreline and the built environment at its edge.

In addition to natural disasters and accompanying inundation events, rising sea levels threaten coastal cities. Decisions about the built environment may soon include whether to relocate some large coastal cities, such as Miami, or to build and maintain extensive seawalls to protect the existing infrastructure. Mass relocation of coastal cities would create a huge national economic burden, whether the cities rebuild inland or people disperse to other metropolitan areas.

Water Quality

Society pays a significant cost to monitor and maintain the complex built infrastructure supporting drinking-water access, treatment, and distribution. However, the component of the built environment with the greatest impact on drinking water is the wastewater conveyance system.

Insufficient investment in water treatment creates additional risks and downstream costs. Infectious microbes from sewage can enter water resources from septic system failures and from combined sewer overflows during heavy rainfalls. Wastewater treatment choices can also influence land-use patterns. For example, land developers install OWTSs in new housing developments located in areas beyond the reach of existing public sewer systems. Each housing unit requires a relatively large parcel of land to ensure that a sufficient wastewater drainage field for the system will operate properly. Thus reliance on septic tanks for on-site wastewater treatment prevents the development of dense, pedestrian- friendly communities that can contribute to a healthy overall lifestyle.

Building sewer systems eliminates the need for large land parcels for individual housing units, and building density can be much higher than is possible in communities using OWTSs. However, once the sewer system exists, failure to invest in sewer maintenance and upgrades can also lead to large future costs, including fines for failure to maintain local water quality and the need to redirect limited resources toward emergency repairs. For example, since the 1980s, Atlanta has struggled to meet the increasingly stringent federal Clean Water Standards with an aging infrastructure dating back to the 1880s. The city was fined $38 million (more than $10,000 each day) for polluting the nearby Chattahoochee River. In 2002, Atlanta announced a new initiative, Clean Water Atlanta. Over the ensuing twelve years, the city planned to spend $3.8 billion to protect drinking water, remediate combined sewer overflows, improve the sanitary sewer system, and create water reclamation centers and other system improvements. Atlanta mayor Shirley Franklin made these improvements a top priority and called herself the Sewer Mayor. A combination of a special local option tax, low-interest loans, and federal appropriations funds Clean Water Atlanta. However, more than $1 billion in direct costs burden local customers (Clean Water Atlanta 2010), and planned rate increases will result in extraordinarily high monthly water bills for city residents (Food & Water Watch 2009).

Climate Change, Water, and Health

The impacts of climate change are issues already discussed, such as permanent drought conditions in the southwestern United States and the impact of heavier precipitation on water conveyance structures and receiving waters. Another anticipated impact includes direct damage to water conveyance infrastructure in coastal and island communities from rising sea levels and more severe storm surges. In addition, there will be increased competition for water resources among communities with growing populations, an expanding energy sector needing water for cooling, and an increasing need for irrigation to support agriculture (Climate Change Science Program 2008).

Issues in Developing Countries

Most of this chapter has focused on developed countries; however, water and sanitation are critical public health issues in developing countries. Whether water shortages are of shorter or longer durations, seasonal or permanent, the direct effects of too little water include poorer sanitation (less hand washing, less drinking water, and less cleaning) and less water available to irrigate crops. The lack of the basic infrastructure that is essential to improve access to clean water thwarts attempts to bring even minimal sustainable water protection technology to some remote areas. However, small-scale options can be successful. For example, the nongovernmental organization Water Missions International (2011) creates local community partnerships in which the NGO provides technology (such as a small-scale water chlorination facility) and community members implement pre- and post-installation projects, such as building an animal-proof structure for the facility and providing ongoing system maintenance.

On a larger scale, an example of how careful planning can secure a lasting water supply is the water management strategy implemented in Windhoek, Namibia, where city managers integrated policies, legislation, education, technical enhancements, and financial support to develop an extensive and successful water reclamation and conservation effort. Namibia is flanked by the Namib and Kalahari deserts, and more than 80 percent of the country itself is desert. Windhoek, Namibia’s capital, is located 1,540 feet above sea level, with an annual rainfall of fifteen inches. Concerned that central Namibian water resources could not provide a reliable future water source (Lahnsteiner and Lempert 2007), the Windhoek city council approved a comprehensive water management program in 1994 (Van der Merwe 2000). Windhoek’s water is supplied by surface water from reservoirs, groundwater from municipal boreholes, and reclaimed water from the New Goreangab Water Reclamation Plant (NGWRP) (nearly 25 percent of the potable water) and the Old Goreangab Water Reclamation Plant (not fit for human consumption but used for irrigation) (Lahnsteiner and Lempert 2007). During years of average or better rainfall, surface water is adequate. Water from municipal boreholes can augment the potable-water supply during about four years of drought. Municipal wastewater is treated and discharged into ponds, and the final effluent is a raw water source for the NGWRP. Industrial wastewater is treated and reused to irrigate pastures. Treated surface water recharges municipal boreholes. In addition to wastewater reclamation, the city introduced water conservation laws that are rigorously enforced during droughts, such as watering gardens during times of low evaporation and covering swimming pools when not in use. Consumption-related water pricing, technical improvements such as reducing water loss and preventing water pollution, and public education have reduced per capita consumption.

Policy Approaches to Clean, Ample Water

Many countries now recognize that solutions to water shortages, water scarcity, and declines in water quality require an integrated approach that includes water conservation and alternate sources, such as treated wastewater. Policy decisions to conserve and protect water resources can be highly effective. Local government and planning-committee rulings can support watershed protection, limit development in small watersheds, and require conservation measures. Large-scale policy decisions can address questions about whether to use available resources to protect watersheds or to build infrastructure to treat contaminated water. Choices to support conservation measures and best practices for regional or national water resources involve larger-scale decisions made at the appropriate political level. For example, the goal of providing substantial water resources through wastewater recycling required the national governments of Singapore and Namibia to prioritize water recycling, develop water treatment processes, and create critical public relations campaigns to garner nationwide support.

New York City provides a good example of the value of watershed protection (New York City DEP 2011). The first public well in the United States was dug in Manhattan in 1677. As the city grew, new water resources were developed, and reservoirs and water distribution systems were constructed. As the available water supply became polluted and insufficient, the city built aqueducts and reservoirs but continued to outgrow its water resources. In 1905, the state legislature created the Board of Water Supply, and the city decided to develop the Catskill region in upstate New York as a water resource. In 1989, the EPA promulgated the Surface Water Treatment Rule, which required all public water systems supplied by unfiltered surface water sources to either provide filtration or meet the criteria required to avoiding filtering the water; these criteria were a series of water-quality, operational, and watershed controls. Rather than invest in costly new drinking-water treatment systems, New York City applied for the filtration waiver for its upstate watersheds. A team of stakeholders created an agreement that would allow the city to advance its watershed protection program while protecting the economic viability of watershed communities. The city secured a five-year waiver from the EPA requirement to filter raw water before further treatment. Today New York City utilizes one of the largest unfiltered surface water sources in the world, delivering more than one billion gallons of treated water, or more than 90 percent of the city’s demand, to 8 million residents each day.

Summary

Access to safe potable water is one of the most important environmental public health challenges. Homeowners, communities, metropolitan areas, and entire nations face temporary or sustained water shortages that must be addressed when considering the public health impact from the built environment. As demonstrated in the examples throughout this chapter, neglecting the water conveyance infrastructure can prove disastrous. Conservation measures and carefully constructed reuse can deliver adequate sustainable services, including clean tap water.