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1 9. Water and Wastewater Systems

2 9.1. Introduction

3 Water and wastewater systems represent essential infrastructure for sustaining the economic and social 

4 viability of a community. Although these systems provide basic public health and safety to homes, 

5 businesses, and industry, they are often taken for granted because of the high level of service and 

6 reliability provided by water and wastewater utilities. The importance of these systems is not recognized 

7 until a water main break or other disruption in service occurs. This chapter addresses disaster resilience of 

8 public water and wastewater systems.

9 While some utilities are already taking steps to improve the resilience of their systems, capital 

10 improvement programs and many others often focus on performing emergency repairs, increasing system 

11 capacity to meet population growth, or making system improvements to satisfy public health and 

12 environmental regulations. Replacing buried pipelines is often delayed until water main breaks become 

13 frequent or wastewater pipeline groundwater infiltration rates create excessive demand on the treatment 

14 system. Communities have a perfect opportunity to couple resilience with future/planned retrofits or 

15 replacements of old infrastructure, to improve the resilience of water and wastewater infrastructure. This 

16 chapter focuses on the water and wastewater infrastructure itself. However, the water and wastewater 

17 industry faces challenges beyond just the infrastructure performance. Water quality and environmental 

18 impact are two of the biggest concerns. For example, if water of poor quality is delivered to customers, 

19 there is significant risk that the public may become ill from consumption. The wastewater industry 

20 operates within strict environmental constraints that have and will likely continue to become more 

21 stringent. These restrictions prevent excessive pollution that contribute to environmental damage and, 

22 ultimately, impact the health of the humans and animals. Although this chapter touches on such 

23 challenges, its main focus is how to build a more resilient infrastructure system that will deliver good 

24 quality water with fewer disruptions and limit damage to wastewater systems, making spills less frequent. 

25 9.1.1. Social Needs and Systems Performance Goals

26 Water services are essential to our daily lives. Using USGS data, Aubuchon & Morley (2012) calculated 

27 the average consumption of water across all U.S. states to be 98 gallons per person per day. However, 

28 water consumption varies by community and by customer. Personal uses include water for drinking and 

29 cooking, personal hygiene, flushing toilets, laundry, landscape irrigation, and many others. Many 

30 businesses and industries also depend on a continual supply of potable water and wastewater collection 

31 services. Absent functioning drinking water and wastewater systems, the operation of restaurants, child 

32 care facilities, hotels, medical offices, food processing plants, paper mills, etc., significantly 

33 compromised, if not completely impossible. Additionally, water systems in urban and suburban areas 

34 provide water supply for fire suppression. Chapter 2 discusses this societal dependence on water and 

35 wastewater systems and other infrastructure systems in more detail.

36 In the United States, communities generally accommodate to short-term (on the order of a few days) 

37 disruptions in water and wastewater services resulting from man-made or natural hazard events. However, 

38 longer-term disruptions are less tolerable. The Oregon Resilience Plan (OSSPAC, 2013) indicated a 

39 business that cannot reoccupy facilities (including functioning water and wastewater systems) within one 

40 month would be forced to move or dissolve. This timeline likely varies depending on community needs 

41 and the severity of the event. Water and wastewater utility providers need to work with customers and 

42 regulatory agencies to establish realistic performance goals for post-disaster level of service, evaluate 

43 their systems’ status in relation to those goals, and then develop strategies to close the identified resilience 

44 gaps. Flow, pressure, and water quality should be considered in those performance goals. 
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45 9.1.2. Interdependencies

46 As discussed in Chapter 4, water system operations are interdependent with other infrastructure systems,

47 both for day-to-day operation and restoration following a hazard event. Electric power is one of the most 

48 important services necessary for maintaining pumping and treatment operations. Transportation is critical 

49 to allow access for inspection and repairs after the event, as well as maintaining the supply chain. Figure 

50 9-1 presents some interdependencies of the water infrastructure system with other infrastructure systems. 

51

52 Figure 9-1. Water Interdependencies with Other Infrastructure Systems (Morley 2013)

53 Some of the most important dependencies for the water and wastewater infrastructure systems include:

54 1. Energy/Power (Electric and Fuel/Petroleum) – Water and wastewater utilities rely on 

55 commercial electricity to run pumps, treatment processes, and lab and office operations. Some of 

56 these functions may have standby power, but overall power demands make it impractical for most 

57 water and wastewater systems to run entirely on standby generators. However, short-term power 

58 loss events are often mitigated by standby generators supported to maintain water and wastewater 

59 operations. These emergency conditions are dependent on sustained fuel supply for standby 

60 generators to support utility vehicles and equipment. Disruption in fuel production, storage, or 

61 delivery may severely impact a water utility’s ability to sustain operations on standby generator 

62 power and perform repairs. 

63 2. Transportation (Staff, Supplies, Pipelines) – Staff at water and wastewater facilities depend on 

64 roadway and bridge transportation systems for access. Damage to transportation infrastructure 

65 potentially complicates and lengthens repair times or even prevents repairs until roadways and 

66 bridges are usable. Water and wastewater utilities generally keep a limited stock of pipe, fittings, 

67 and other repair materials to use in response and recovery operations. However, depending on the 

68 size of the event, this stock may be quickly depleted due to supply chain disruptions. Such 

69 disruptions may also impact the available support from relief equipment and personnel. Utilities 

70 also rely on a semi-regular delivery of treatment process chemicals essential for meeting water 

71 quality regulations.
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72 Water and wastewater buried pipelines are often co-located with other buried infrastructure under 

73 or adjacent to roadways. Failure of pipelines may result in damage to the roadway (e.g., sinkhole 

74 from water main break or collapsed sewer pipeline) and impact to traffic during repairs. 

75 Therefore, the transportation system, particularly the roadway system, is dependent on the 

76 performance of the water and wastewater infrastructure systems.

77 3. Communications and Information – Water and wastewater utilities often rely on cellular 

78 networks to communicate to operations staff and contractors. If the cellular network is down for 

79 an extended period, complications and delays in repairs can occur. Additionally, supervisory 

80 control and data acquisition (SCADA) networks are used extensively within both water and 

81 wastewater systems to monitor and control widespread components and equipment. 

82 The communications system infrastructure also depends on water infrastructure. For example, air 

83 conditioning system cooling towers that support communications require water to keep sensitive 

84 electronic equipment in Central Offices at safe operating temperatures. Furthermore, technicians 

85 cannot enter Central Offices to maintain or repair functionality of the communications system if 

86 its water and wastewater systems are not functioning.

87 4. Buildings (Critical, Commercial, General Public) – Water and wastewater utilities rely on 

88 customers (e.g., critical facilities, commercial facilities, and households) to pay bills as a 

89 continued source of capital. Utilities will potentially experience significant capital expenditures in 

90 the aftermath of a disaster and customers may not have the ability to pay bills (i.e., loss of 

91 personal income from loss of wages or breakdown of electronic or posted payments), placing a 

92 large financial burden on the utilities. Water and wastewater utilities also operate administrative 

93 buildings. New Orleans Water & Sewer Board’s treatment, distribution, collection, and 

94 administrative operations were severely impacted following Hurricane Katrina. The 

95 administration’s disruptions included the loss of customer billing and other records due to 

96 significant flooding. During this same event, Children’s Hospital of New Orleans was forced to 

97 evacuate when the hospital lost water pressure and was unable to maintain the HVAC system 

98 needed by patients in critical care units.

99 Commercial and other public buildings need water supply with adequate flow and pressure for 

100 fire suppression, as well as sanitation. Industrial facilities need functional water and wastewater 

101 systems for developing, processing, and manufacturing materials and products. The public relies 

102 on water and wastewater services for overall health of the community.

103 9.2. Water and Wastewater Infrastructure

104 This section describes basic components of water and wastewater systems. Performance observations 

105 from past disaster events characterize some key hazard vulnerabilities in water and wastewater systems.

106 Water and wastewater infrastructure are vulnerable to a number of hazards: buried pipelines are 

107 vulnerable to breaks during earthquakes, water and wastewater treatment facilities are vulnerable to flood 

108 hazards. Facilities are often designed to be in or near flood hazard areas, given their functional 

109 dependency on natural water resources. To become more resilient, each individual community will have 

110 to consider its own hazards when implementing plans. Additionally, as discussed in the previous section, 

111 system interdependencies (e.g., loss of commercial electrical power in a high wind event) can have a 

112 significant impact on operability of water and wastewater systems (Elliott, T. and Tang, A., 2009).

113 9.2.1. Water Infrastructure

114 Water sources include groundwater and surface water, treated to satisfy public health standards and 

115 distributed to consumers by a network of pipelines. Some water utilities have their own supplies and 

116 treatment infrastructure, while others buy wholesale water from neighboring agencies.

117 Water systems are composed of six general infrastructure categories: 1) Supply, 2) Transmission, 3)

118 Treatment, 4) Pumping, 5) Storage, and 6) Distribution. The basic function of each category and 
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119 infrastructure system (electric power, transportation, communication) interdependent of the water system

120 can be impacted by a variety of hazards, as shown in Table 9-1. Some examples of damage to water 

121 infrastructure seen in past events are discussed in the following subsections.

122 Table 9-1. Hazard Impacts on Water Infrastructure System (AWWA M19: Emergency Planning for 

123 Water Utilities)

124

125 9.2.1.1. Supply

126 Water supply can come from groundwater or surface water, as described below.

127 Groundwater. Rainfall and snowmelt infiltrate into the ground to recharge groundwater aquifers. 

128 Groundwater wells tap into aquifers and supply water to individual households or municipal water 

129 providers. A well system consists of the groundwater aquifer, well casing and screen, pump and motor, 

130 power supply, electrical equipment and controls, connecting piping, and possibly a well house structure. 

131 Typically, wells are cased with a steel pipe. Screens in the well casing at the depth of the aquifer allow 

132 water to enter the casing. A submersible or surface-mounted pump conveys water to the transmission 

133 system.

134 Surface Water. Rainfall and snowmelt runoff that does not infiltrate into the ground collects in streams, 

135 rivers, and lakes, and is sometimes impounded by dams. Water intake structures in lakes or rivers and

136 diversion dams then direct water to a pipeline inlet along the shoreline. All of these systems would 

137 generally include screens to keep large debris and fish from entering the treatment plant.

138 Just as with water and wastewater infrastructures, the water supply is particularly vulnerable flooding and 

139 earthquakes. The most significant hazard is contaminated water; flooding can cause contamination of 

140 surface and groundwater sources. Additionally, inundated well heads at the surface can introduce 
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141 contaminants to well systems and groundwater. Floodwaters and generally carry contaminants like 

142 petroleum, nutrient/organic matter, bacteria, protozoa, and mold spores that pose significant health risks.

143 Contamination can also result from tank or vehicle discharge in the watershed. In 2014, in West Virginia, 

144 4-methylcyclohexanemethanol (MCHM) was released into the Elk River, contaminating water serving 

145 300,000 people. It took months to restore full water service.

146 Although not often considered for their impact on water quality, wildfires can also lead to water 

147 contamination. Wildfires can burn watersheds, destabilizing the ground cover, which can cause landslides

148 that contaminate the water when subsequent rains occur. Denver Water experienced wildfires in 

149 significant parts of their watershed in 1996 and 2002 that burned 150,000 acres of land, releasing one

150 million cubic yards of sediment into one of their reservoirs.

151 Reservoirs behind dams often also serve as water supply features, but dam failure can present a secondary 

152 hazard in the wake of earthquakes, heavy rainfall, and flood events. Concentrated precipitation and 

153 flooding most commonly causes overtopping of the dam. While dams can reduce flooding, older and 

154 improperly designed and maintained dams are not equipped to contain large volumes of quickly 

155 accumulating water runoff. Landslides, caused by liquefaction from earthquakes can also lead to dam 

156 failure. These types of dam failures are rare, but present a significant risk to anyone’s life downstream of 

157 a dam. Dams are critical infrastructure components that need to be designed to withstand extreme events.

158 9.2.1.2. Transmission

159 Large diameter transmission pipelines carry raw water 

160 from source to treatment plant, and treated water to 

161 storage facilities before branching out into smaller 

162 distribution pipelines. Depending on the system, these 

163 can range from one foot to several tens of feet in 

164 diameter. Transmission pipelines are constructed of

165 welded steel, reinforced concrete, concrete cylinder, or 

166 ductile iron (historically cast iron).

167 Typically, these pipelines are buried, making them 

168 difficult to inspect and expensive and disruptive to 

169 repair. Burial reduces pipelines’ vulnerability to 

170 hazards, such as high wind events; however, hazards 

171 that cause landslides, such as earthquakes, floods, 

172 long-term heavy rain, and wildfire, can damage 

173 transmission lines. Figure 9-2 shows a transmission 

174 pipeline bridge demolished in the Bull Run Canyon in 

175 a landslide event induced by heavy rains.

176 9.2.1.3. Treatment

177 Water treatment plants process raw water from groundwater or surface water supplies to meet public 

178 health water quality standards and often to improve taste. The processes used depend on the raw water 

179 source, removing pathogens, organic or inorganic contaminants, chemicals, and turbidity. The treatment 

180 process commonly includes pretreatment, flocculation, sedimentation, filtration, and disinfection with 

181 variations of these processes in some modern plants. Water treatment plants typically consist of a number 

182 of process tanks, yard and plant piping, pumps, chemical storage and feed equipment, lab and office 

183 building space, and associated mechanical, electrical, and control equipment.

184 Water treatment plants are vulnerable to flooding, because they are often located near flooding sources 

185 (i.e., lakes, rivers). Electrical control systems are often damaged by flood inundation, leading to loss of 

186 functionality and service outages. In 1991, the Des Moines, Iowa Water Treatment Plant was submerged 

187 by riverine flooding, resulting in 19 days without potable water for the city of Des Moines.

Figure 9-2. Water Transmission Pipeline Bridge 

Damaged by Landslide (Courtesy of Portland 

Water Bureau)
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188 Loss of power at water treatment plants from high wind events (hurricanes, tornadoes), severe storms, or 

189 other hazards can severely impact the system by preventing proper treatment prior to transmission and 

190 distribution. As a result, potable water may not be available and boil water notices necessary. While 

191 standby power systems are usually incorporated into a water treatment plant’s design, they need to be 

192 well-maintained, tested regularly, and adequately connected, installed, supplied, and protected from 

193 hazard events to be reliable and function properly.

194 Earthquakes also cause damage to water treatment plants and their components. In 1989, the Loma Prieta 

195 earthquake in California heavily damaged the clarifiers due to sloshing water at the Rinconada Water 

196 Treatment Plant in San Jose, California, greatly curtailing its 40 MGD capacity (Figure 9-3). In the 2011 

197 Tohoku earthquake in Japan, liquefaction resulted in differential settlement between pile-supported 

198 structures and direct-buried pipe at water treatment plants, as shown in Figure 9-4.

Figure 9-3. Santa Clara Valley Water District, 

Rinconada Water Treatment Plant Clarifier 

Launders Damaged due to Sloshing, 1989 Loma 

Prieta Earthquake (Courtesy of Don Ballantyne)

Figure 9-4. Liquefaction Caused Differential Settlement 

Between Pile-Supported Structures and Buried Pipe 

during the 2011 Tohoku Earthquake (Courtesy of Don 

Ballantyne)

199 9.2.1.4. Pumping

200 Pumping stations increase hydraulic head (i.e., raise water from one elevation to a higher elevation). A 

201 pump station typically consists of a simple building that houses pumps, motors that power the pumps, 

202 pipes, valves, and associated mechanical, electrical, and control equipment. Pump stations often have 

203 standby emergency generators to enable continued operation when commercial power supply is 

204 interrupted.

205 Similarly to water treatment plants, loss of 

206 commercial electrical power due to any type of 

207 hazard event prevents operation of pumps if there 

208 is no standby power supply. Furthermore, 

209 floodwater can inundate electrical equipment and 

210 controls at pump stations located wholly or 

211 partially below grade and/or in flood-prone areas. 

212 Figure 9-5 shows a pump station adjacent to the 

213 Missouri River damaged by flood inundation. 

214 9.2.1.5. Storage

215 Water utilities use storage tanks and reservoirs to 

216 balance water demand with water production 

217 capacity. Stored potable water is drawn down 

218 during times of peak usage and recharged during 

219 off-peak hours. Typically, one to three days of 

Figure 9-5. Bismarck, ND Pump Station Damaged by 

Flood Inundation from Adjacent Missouri River 

(Courtesy of FEMA)
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220 daily water demand is stored to satisfy increased demand from fire suppression or other emergency needs.

221 Reservoirs are often constructed by damning a valley with a concrete or earthen dam. If they are being 

222 used for treated water, they can be lined with asphalt or concrete and covered.

223 Modern steel storage tanks are either ground-supported, taller standpipes, or elevated tanks supported on a 

224 frame or pedestal. Reinforced concrete tanks are typically at grade or buried. Circular concrete tanks can 

225 be reinforced with wire wrapping or tendons.

226 Storage tasks are vulnerable to a number of 

227 hazards. Elevated storage tanks are more 

228 susceptible to hazards from high winds than 

229 structures located at grade and can be damaged to 

230 the point of structural failure, suddenly releasing 

231 their contents. In hurricanes, high winds present a 

232 higher hazard in coastal areas (than further 

233 inland) and are often accompanied by storm 

234 surge. Figure 9-6 shows a collapsed water tank in 

235 Buras, Louisiana near Hurricane Katrina’s 

236 landfall that was likely caused by a combination 

237 of high winds and storm surge.

238 At-grade or partially-underground storage tanks 

239 are more susceptible to flood damage (from 

240 hurricane storm surge, riverine flooding, or 

241 tsunamis), particularly if located in or near flood242 prone areas. Tank damage or failure can be 

243 caused by both hydrostatic forces from standing 

244 or slow moving water, or hydrodynamic forces 

245 imposed by higher velocity flows or wave action. 

246 Buoyancy forces can cause uplift of empty 

247 subgrade tanks if the soil becomes saturated.

248 Figure 9-7 shows two liquid fuel tanks in the 

249 foreground that were floated and toppled by 

250 tsunami wave inundation after the 2011 Tohoku,

251 Japan tsunami. The tank in the background was 

252 on higher ground and does not appear to be 

253 damaged.

254 Earthquakes can damage storage tanks due to 

255 lateral loads (shaking) and permanent ground 

256 deformation due to liquefaction and landslides. Water sloshes in storage and process tanks imparting

257 extreme loads on tank walls and baffles. In the 1994 Northridge earthquake, a Los Angeles Department of 

258 Water and Power (LADWP) tank moved, severing piping, as shown in Figure 9-8. The utility just north 

259 of LADWP suffered elephant’s foot buckling in a steel tank as shown in Figure 9-9. 

260

Figure 9-6. Collapsed Water Tank in Buras, LA near 

Hurricane Katrina Landfall Location (Courtesy of

David Goldbloom- Helzner)

Figure 9-7. Steel Tanks Damaged Due to Tohoku, 

Japan Tsunami in 2011 (Tang & Edwards 2014)
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Figure 9-8. Tank Moved, Severing 

Connecting Pipe in 1994 Northridge 

Earthquake (Courtesy of Los Angeles 

Department of Water and Power)

Figure 9-9. Steel Tank “Elephant’s Foot” Buckling in 1994 

Northridge Earthquake (Courtesy of Donald Ballantyne)

261 9.2.1.6. Distribution

262 Smaller diameter distribution pipelines carry treated water from transmission pipelines to neighborhoods 

263 commercial and industrial areas. Service connections with meters branch off distribution pipelines to 

264 supply individual customers. The portion of the service connection before the water meter is typically 

265 maintained by the water utility and the portion after the water meter is the responsibility of the individual 

266 customer. The system is controlled with manually operated valves distributed at most pipeline 

267 intersections. Distribution systems have fire hydrants located every 300 feet along the pipeline. 

268 Distribution pipelines are commonly made with ductile iron (historically cast iron), welded steel, PVC, or 

269 asbestos cement.

270 Leaks and breaks are two main concerns for distribution pipelines. A leak commonly refers to relatively 

271 minor damage to a pipe barrel or joint that causes minor to moderate water loss, but does not significantly 

272 impair the distribution system’s function. However, breaks commonly refer to major damage to a pipe 

273 barrel or joint that causes major water and pressure loss in a zone or drains nearby tanks. When there are 

274 breaks in the water distribution system, it can lead to depressurization of the system. Depressurization can 

275 result in sediment accumulation within the pipelines affecting the potability of the water, contamination 

276 and loss of potability means boil water orders should be issued. Before water can be considered potable 

277 again, the distribution systems must be fixed and the water quality monitored and tested continuously to 

278 meet public health standards. 

279 Breaks of distribution pipelines can result from a number of hazards. Floods cause erosion, exposing, 

280 possibly breaking pipelines (see Figure 9-10). 
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Figure 9-10. Exposed and Broken Distribution Lines Resulting from Flooding in Jamestown, CO (Courtesy of 

David Goldbloom-Helzner)

281 Earthquakes can cause liquefaction or permanent 

282 ground deformation, causing pipeline breaks. In the 

283 1994 Northridge earthquake, the Los Angeles 

284 Department of Water and Power had approximately 

285 1,000 pipeline breaks, primarily in cast iron pipe. 

286 While there was only limited liquefaction, ground 

287 motions were very strong. A year later, the Kobe 

288 earthquake caused approximately 1,200 pipeline 

289 failures due to extensive liquefaction. Most of the 

290 system was constructed of ductile iron pipe, which 

291 primarily failed by joint separation as seen in Figure 

292 9-11.

293 High wind events, such as hurricanes or tornadoes, 

294 can result in damage to distribution lines, though not 

295 directly cause by high winds, but by uprooted trees. 

296 For example, during Hurricane Andrew, there was 

297 extensive damage to the water distribution systems 

298 in Southern Florida primarily caused by tree roots that had grown and wrapped themselves around the 

299 water mains and service lines. When these trees were uprooted by hurricane force winds, (Hurricane 

300 Andrew was a Category 5 on the Saffir-Sampson scale when it made landfall in Dade County, Florida) 

301 they pulled the lines too. Similar damage to water transmission and distribution systems occurred during 

302 Hurricanes Katrina and Rita in Louisiana (Allouche, 2006). As stated above, no matter the cause of 

303 damage, pipeline breaks resulting in a depressurized system contaminate the pipelines, affecting the 

304 potability of the water and requiring additional recovery time.

305 9.2.2. Wastewater Systems

306 Wastewater systems collect domestic and industrial liquid waste products and convey them to treatment

307 plants through collection and conveyance systems and pump stations. After separation of solids, 

308 biological processing and disinfection, treated wastewater is discharged as effluent into a receiving body 

309 of water or alternatively, may be reused for irrigation or other purposes. Some utilities have separate 

310 collection systems for wastewater and storm water; other utilities have collection systems combine 

311 collected wastewater and storm water in the same pipelines.

312 Pipeline system failure can discharge raw sewage into basements, on to city streets, and into receiving 

313 waters, resulting in public health issues and environmental contamination. Standard wastewater systems 

Figure 9-11. Joint Separation in Ductile Iron Pipe 

due to Liquefaction during 1995 Kobe Earthquake 

(Courtesy of Kobe Water Department)
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314 are composed of five general categories of infrastructure: 1) Collection, 2) Conveyance, 3) Pumping, 4) 

315 Treatment, and 5) Discharge. The basic function of each of these categories is briefly described in the 

316 following subsections. Apart from standard systems, pressure and vacuum systems are used on occasion. 

317 Pressure systems require a grinder pump at each house that pump the sewage through small diameter pipe 

318 to a larger pipe collector, and often times to a gravity sewer. Vacuum systems work in a similar manner,

319 except a vacuum pump and tank pull sewage through shallow small diameter pipe to a central location.

320 9.2.2.1. Collection

321 The collection pipeline network for wastewater systems is similar to that for water systems, except instead 

322 of delivering water to individual customers the wastewater collection system conveys liquid and other 

323 waste products away from customers. This is usually accomplished using gravity sewers. In some 

324 instances pumps convey wastewater through pressurized force mains. The elevation and grade of the 

325 pipelines in the system need to be carefully controlled to maintain gravity flow in the system. Infiltration 

326 and inflow of groundwater into the collection system through cracks and breaks in the pipe can 

327 significantly increase the volume of wastewater that arrives at the treatment plant. A variety of pipe 

328 materials are commonly found in collection systems, including: 

329  Vitrified clay – smaller diameter collection

330  PVC – smaller diameter collection

331  Asbestos cement – historically smaller diameter collection

332  Reinforced concrete – larger diameter interceptors

333  Steel – force mains or siphons

334  Polyethylene – force mains or siphons

335  Ductile iron (or historically cast iron) – collection or force mains

336  Brick – larger capacity interceptors

337  Fiberglass or FRP

338  ABS

339 Gravity systems have manholes at regular intervals allowing access for cleaning and maintenance. 

340 Manholes are usually constructed with concrete, although historically manholes were often constructed 

341 with brick. 

342 Wastewater collection pipes have similar causes of damage to those of water distribution and transmission 

343 pipelines. Wastewater collection pipelines can be exposed and damaged because of landslides, erosion, or 

344 scour, which damages or breaks the pipelines. Furthermore, wastewater collection pipelines can be 

345 damaged in high wind events by uprooted trees with root systems grown around the pipelines.

346 In the collection and conveyance system, pipelines are damaged by earthquake shaking, but more 

347 extensively due to liquefaction and associated lateral spreading. Sewer pipes can be damaged by shaking,

348 which can cause joints to crack, but most remain operable. These cracks will ultimately have to be 

349 repaired to control infiltration. Liquefaction can result in pulled joints and displaced pipe. Another cause 

350 of failure is pipe flotation, occurring when a partially-filled gravity sewer is surrounded by liquefied soil.

351 Flooding can also damage wastewater collection pipelines in a number of ways. Pipelines that are co352 located on bridges experience damage caused by flood inundation and flood-borne debris impact. 

353 Hydrodynamic forces associated with coastal flooding or high velocity flows are more likely to damage 

354 structures and attached pipelines than inundation alone. In the New Orleans area after Hurricane Katrina, 

355 the most common damage to buried wastewater pipelines observed by clean-up crews was separation of 

356 pipe joints, leaks, and breaks. This damage was believed to be the result of floodwaters supersaturating 

357 soils then draining, leading to soil shrinkage and subsidence. Without support of the soils, the rigid 

358 pipelines broke and fractured (Chisolm, 2012). Increased flow and pressurization of the wastewater 
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359 collection systems as the result of inflow and infiltration during flood events can also damage pipelines,

360 particularly in cases where pipes are composed of materials such as vitrified clay. For example, during the 

361 1997 Red River Flood in Grand Forks, North Dakota, pressurization caused breaking of vitrified clay pipe 

362 and hairline cracks increased the rate of overall pipe deterioration (Chisolm 2012).

363 9.2.2.2. Conveyance

364 The conveyance system for the wastewater network is similar to the transmission system in a water 

365 system. The conveyance pipelines are larger in diameter, and are often times deeper underground. In 

366 many instances, these conveyance systems were installed in the early to mid-1900s as the United States 

367 began to clean up its waterways. The conveyance systems are designed to collect sewage from the 

368 collection system and move it to the wastewater treatment plant. Like collection systems, it may include 

369 pump stations. Recently, the EPA is pushing wastewater utilities to minimize discharge of raw sewage to 

370 receive water runoff during heavy rain events. This often resulted in cities having sewers that carried both 

371 sewage and storm water. As a result, many conveyance systems now have a built-in large storage 

372 capacity, taking the form of a wide point in the line and, in some cases, simplified wastewater treatment 

373 facilities.

374 9.2.2.3. Pumping

375 Gravity feed systems use pump or lift stations to lift wastewater to a higher elevation. The pump may 

376 discharge at the higher elevation to another section of gravity feed pipeline or may remain a pressurized 

377 force main and discharge at a distant location, such as a treatment plant. A pump station typically consists 

378 of a simple building that houses pumps, motors that power the pumps, pipes, and associated mechanical, 

379 electrical, and control equipment. The pumps can be located in a building (typically wetwell-drywell 

380 layout) or a large manhole (submersible). Pump stations are required to have standby generators to enable 

381 continued operation when the commercial power supply is interrupted.

382 Pump stations are vulnerable to a number of hazards, most notably earthquakes and flooding. Unless 

383 designed to be submersible, floodwater inundating pumps can disable and damage the pumps and their 

384 motors. This was a common cause of pump station failure in New York City during flood inundation 

385 from Hurricane Sandy (NYCDEP, 2013). Damage is even worse if salt water flooding is involved,

386 leading to corrosion. Loss of commercial electrical power prevents operation of pumps if adequate 

387 standby power is not provided or these generators are not refueled in a timely manner. Earthquakes can 

388 cause liquefaction, resulting in buried wastewater collection wells at pump stations to float and tilt. This 

389 movement likely damages connecting piping and renders the pump station inoperable. Manholes and 

390 pump stations can float as well, when founded in liquefied soils, which changes the grade, making the 

391 sewer unusable or difficult to maintain. 

392 9.2.2.4. Treatment

393 Wastewater treatment plants process raw sewage from household and industrial sources so the resulting 

394 effluent discharge meets public health and environmental standards. The typical process is: 1) 

395 Pretreatment using screens and grit chambers, 2) Primary treatment in a sedimentation tank, 3) Secondary 

396 treatment using biological treatment and clarifiers, and 4) Disinfection using chlorine or other 

397 disinfectants. In some cases, the effluent is further treated at a higher level to be used for irrigation. Solids 

398 drawn off from the four processes are further treated in digesters and solidified using presses or 

399 centrifuges. These processes require an extensive mechanical and electrical equipment and piping.

400 Wastewater treatment plants are susceptible to damage from several natural hazards, particularly flooding.

401 Wastewater treatment plants are often located in or near flood-prone areas because they return treated 

402 water to naturally occurring bodies of water via gravity. Therefore, they can be vulnerable to flood 

403 inundation or storm surge and wave action from coastal sources, causing damage and loss of functionality 

404 to buildings, equipment, and electrical and mechanical systems. The New York City Department of 
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405 Environmental Protection (NYC DEP) noted in a recent study that all 14 of the wastewater treatment 

406 plants (WWTP) it owns and operates are at risk of flood damage (NYCDEP, 2013). 

407 WWTPs in non-coastal regions of the United States are often located adjacent to rivers. With the 

projected sea level rise continuing through the 21st 408 century, the frequency of these facilities flooding will 

409 increase. Some recent examples of WWTP riverine flooding include: 1) Nine days of lost functionality 

410 due to flooding of Valdosta, Georgia WWTP in 2009; 2) Flooding of the Pawtuxet River in Warwick, 

411 Rhode Island in 2010; and 3) Shut down of the Palmyra, Indiana WWTP in 2011 due to rising water 

412 levels. 

413 In areas where wastewater treatment facilities are elevated or protected by levees, flooding can still lead 

414 to access issues. While the treatment facility itself may not be inundated, flooding around the facility can 

415 limit both ingress and egress of vital staff. This was the case for several WWTPs located along the 

416 Missouri and Mississippi Rivers during the 1993 flood. Access to facilities was only possible by boat, 

417 while roads inundated by the flood were not considered stable enough for larger vehicles, such as those 

418 that carried supplies for the plants (Sanders, 1997).

419 Release of untreated sewage is relatively common during major flood events when inflow and infiltration 

420 can overtax wastewater collection systems or when there are combined sewer overflows. During 

421 Hurricane Sandy, over 560 million gallons of untreated and diluted sewage, mixed with storm water and 

422 seawater, was released into waterways. This instance of sewage release was caused by infiltration of 

423 floodwaters into the sewer system, flood inundation of plant facilities, and power outages (NYC DEP, 

424 2013). After Hurricane Sandy, electronic controls were inundated and damaged in many wastewater 

425 treatment facilities, which significantly delayed the facilities’ recovery times (FEMA 2013). Similarly, 

426 after Hurricane Rita in 2005, the City of Lake Charles had a citywide power loss that affected the 

427 wastewater treatment plant serving two-thirds of the city, releasing raw sewage into a nearby lake for over 

428 a week, until power was restored.

429 While discharge or raw sewage contaminates the receiving water, chemical contamination of sewage can 

430 impact the WWTP treatment process itself. For example, in the 1989 Loma Prieta earthquake in 

431 California, the East Bay Municipal Utility District (EBMUD) WWTP biological treatment process failed 

432 due to a spill in the collection system contaminating the treatment plant influent. Coupled with the spill, 

433 EBMUD lost power and were unable to pump oxygen into the treatment system, resulting in the 

434 secondary treatment system being inoperable for several weeks.

435 WWTPs are at a low point in the elevation of the system. Though flooding from different hazard events 

436 (hurricane storm surge, coastal and riverine flooding, and tsunamis) is a primary concern, earthquakes can 

437 damage facilities by shaking, permanent ground deformation, and liquefaction. Shaking is particularly 

438 problematic in process tanks and digesters where the hydraulic load from sloshing sewage impacts the 

439 tank walls. Liquefaction-induced permanent ground deformation often causes process tank joint 

440 separation, damage to pipelines, pipe racks, etc. Even if treatment structures are pile-supported, direct441 buried piping can settle differentially and break. In the 2011 Christchurch earthquake in New Zealand, 

442 clarifiers settled differentially rendering them inoperable. In the 1995 Kobe Earthquake, the Higashinada 

443 WWTP site settled differentially as much a one meter, and moved laterally as much as two meters due to 

444 liquefaction heavily damaging non-pile-supported structures. The resulting damage is shown in Figure 

445 9-12. Figure 9-13 shows the Higashinada influent channel that was offset one meter by liquefaction 

446 during the 1995 Kobe earthquake.
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Figure 9-12. Non-Pile Supported Structures Failed Due to 

Liquefaction in 1995 Kobe Earthquake (Courtesy of Donald 

Ballantyne)

Figure 9-13. Higashinda WWTP Channel Offset 

by Liquefaction in 1995 Kobe Earthquake 

(Courtesy of Donald Ballantyne)

447 Strong earthquakes can produce tsunamis that structurally damage treatment plant facilities due to lateral 

448 hydraulic loading and can inundate facilities, causing damage to electrical gear. The 2011 Tohoku 

449 earthquake in Japan caused heavy damage to the Sendai WWTP Effluent Pump Station’s east wall, as 

450 shown in Figure 9-14. Much of the treatment plant’s process tank equipment required replacement 

451 because of the large amount of damage, as shown in Figure 9-15.

Figure 9-14. Sendai WWTP Effluent Pump 

Station Damaged by Tsunami in 2011 Tohoku 

Earthquake (Courtesy of Donald Ballantyne)

Figure 9-15. Sendai WWTP Equipment and Piping Damage 

from 2011 Earthquake (Courtesy of Donald Ballantyne)

452 9.2.2.5. Discharge

453 Effluent from the treatment plant is discharged to a receiving body of water through an outfall. Outfalls 

454 are composed of a pipeline with a diffuser at the end discharging the water hundreds or thousands of feet 

455 away from the shoreline, at a depth that will minimize impact on the environment.
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456 9.3. Performance Goals

457 The large and distributed nature of water and wastewater systems, combined with their interdependence 

458 on other infrastructure systems, limits the practicality of maintaining 100 percent operational capacity in 

459 the aftermath of a major natural disaster. This section provides an example of performance goals for water 

460 and wastewater systems in the fictional community of Centerville, USA. 

461 Performance goals need to be discussed with individual utilities and communities before they are adopted. 

462 It is important to consider the uniqueness of the infrastructure of individual utilities and the specific needs 

463 of their customers when adopting system performance goals for a community. Water and wastewater 

464 stakeholder engagement is critical in establishing a community-specific level of service performance 

465 goals for each of the three different hazard levels (routine, expected, and extreme) defined in Chapter 3. 

466 Stakeholders should include representation from the following organizations as applicable:

467  Residential customers

468  Business owners 

469  Industry representatives

470  Water wholesale customers 

471  Hospital representatives 

472  Fire department officials and crew

473  Local government officials

474  Local emergency management officials

475  Drinking water regulators (Health Authority, etc.)

476  Wastewater regulators (Dept. of Environmental Quality, Environmental Protection Agency, etc.)

477  Water and wastewater utility operators and engineers

478  Consulting engineers

479  Interdependent infrastructure system operators (power, liquid fuel, transportation, etc.)

480 Establishing performance goals involves a discussion amongst the stakeholders about their expectations 

481 for the availability of water and wastewater systems following a hazard event in the short, intermediate, 

482 and long term phases for different hazard levels (e.g., routine, expected, and extreme). The assumed 

483 expectation of the public is that for routine hazard events there would be little, if any, interruption of 

484 service for water and wastewater lifelines. A dialogue is required between utilities and customers to 

485 determine the appropriate level of service performance goals for expected and extreme events. While 

486 examples are provided in Table 9-2 through Table 9-7 (pages 16 through 21), it is anticipated that actual 

487 goals will vary by community and are dependent on community priorities, as determined during the 

488 development of the goals and through outreach to and discussion among stakeholders. 

489 There may be variability for an individual community’s goals depending on the specific hazard being 

490 addressed. For example, if a community is subject to both seismic and wind hazards, they may determine 

491 that the damage to major collection lines within a wastewater system from an extreme seismic event is 

492 more likely and requires more restoration time, compared to damage from an extreme wind event. 

493 There may be elements in a system that are so critical to public safety they need to be designed to remain 

494 operational after an extreme event. For example, failure of a water supply impoundment dam presents a 

495 significant life-safety hazard to downstream residents and should be designed for an extreme event. 

496 Interdependencies of water and wastewater systems with other infrastructure also need to be considered 

497 when developing performance goals. For instance, availability of a reliable supply of liquid fuel impacts 

498 how long systems can run on standby generators and impacts repair crew’s vehicles and equipment. In 

499 turn, delivery of liquid fuels depends on the status of the highway and bridge transportation network.
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500 Performance goals are broken down into functional categories (i.e., water for fire suppression at key 

501 supply points, treatment plants operating to meet regulatory requirements, etc.) and further broken down 

502 into target timelines to restore the functional categories to 30 percent, 60 percent, and 90 percent 

503 operational status.

504 The infrastructure components in the example performance goals tables are not intended to be an 

505 exhaustive list. Some of the system components may not exist in all communities. For instance, in the 

506 water system performance goals, some communities may have the ability to distinguish between the 

507 general water supply and distribution and water supply for fire suppression. However, most systems are 

508 integrated and will not have a means to separate general supply and distribution from that needed for fire 

509 suppression. Additionally, some communities might have wholesale users – a system component listed in 

510 the performance goals – meaning their water system supplies all of the water used by other nearby, 

511 smaller communities. Wholesale users are treated as a critical part of the distribution system within the 

512 example, but are not a consideration for all communities. Each community will need to review these 

513 components to determine which ones to incorporate into their systems. 

514 Similarly, communities may want to add certain system components to these goals that are not already 

515 captured here, to provide additional detail and allow for distinction between restoration timeframes. There 

516 may also be system components that are unique to a community that require special consideration. While 

517 the lists presented in the examples generally capture significant system components, it is recognized that 

518 communities may have additional infrastructure assets to consider. 

519 The financial burden associated with upgrading all components of an entire system to be more disaster 

520 resilient would overwhelm the short-term capital improvement budgets of most utilities. Therefore, 

521 performance goals have been established around certain concepts.

522  Prioritizing potential solutions to be implemented over many years to limit disruptions and 

523 recovery time rather than implementing them all at once

524  Recognizing that there may be both short and long-term solutions capable of decreasing recovery 

525 times

526  Balancing societal needs with realistic expectations of system performance

527 Focusing on major system components that form a backbone network capable of supplying key health and 

528 safety-related community needs shortly after a hazard event is one way to focus priorities. Recognizing 

529 that potentially less costly short-term solutions combined with longer term physical hardening of 

530 infrastructure allows for increased resilience would manage community’s expectations and the cost of 

531 implementing solutions. 

532
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533 Table 9-2. Example Water Infrastructure Performance Goals for Routine Event in Centerville, USA 

Disturbance Restoration times

(1) Hazard Any (2) 30% Restored

Affected Area for Routine Event Localized 60% Restored

Disruption Level Minor 90% Restored

(3) X Current

534

Functional Category: Cluster

(4) 

Support 

Needed

(5) 

Target 

Goal

Overall Recovery Time for Hazard and Level Listed

Routine Hazard Level

Phase 1 – ShortTermPhase 2 --

Intermediate

Phase 3 – LongTerm

Days Wks Mos

0 1 1-3 1-4 4-8 8-12 4 4-24 24+

Source

1

Raw or source water and terminal reservoirs 90% X

Raw water conveyance (pump stations and 

piping to WTP) 90% X

Potable water at supply (WTP, wells, 

impoundment) 90% X

Water for fire suppression at key supply points 

(to promote redundancy) 90% X

Transmission (including Booster Stations) 1

Backbone transmission facilities (pipelines, 

pump stations, and tanks) 90% X

Control Systems

SCADA or other control systems 90% X

Distribution

Critical Facilities 1

Wholesale Users (other communities, rural 

water districts) 90% X

Hospitals, EOC, Police Station, Fire Stations 90% X

Emergency Housing 1

Emergency Shelters 90% X

Housing/Neighborhoods 2

Drink water available at community 

distribution centers 90% X

Water for fire suppression at fire hydrants 90% X

Community Recovery Infrastructure 3

All other clusters 90% X

535 Footnotes:

1 Specify hazard being considered

Specify level -- Routine, Expected, Extreme

Specify the size of the area affected - localized, community, regional

Specify severity of disruption - minor, moderate, severe

2 30% 60% 90% Restoration times relate to number of elements of each cluster

3 X Estimated restoration time for current conditions based on design standards and current inventory

Relates to each cluster or category and represents the level of restoration of service to that cluster or category

Listing for each category should represent the full range for the related clusters

Category recovery times will be shown on the Summary Matrix

"X" represents the recovery time anticipated to achieve a 90% recovery level for the current conditions

4 Indicate levels of support anticipated by plan

R Regional

S State

MS Multi-state

C Civil Corporate Citizenship 

5 Indicate minimum performance category for all new construction. 

See Section 3.2.6
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536 Table 9-3: Example Water Infrastructure Performance Goals for Expected Event in Centerville, USA

Disturbance Restoration times

(1) Hazard Any (2) 30% Restored

Affected Area for Routine Event Localized 60% Restored

Disruption Level Minor 90% Restored

(3) X Current

537

Functional Category: Cluster

(4) 

Support 

Needed

(5) 

Target 

Goal

Overall Recovery Time for Hazard and Level Listed

Expected Hazard Level

Phase 1 – ShortTermPhase 2 --

Intermediate

Phase 3 – LongTerm

Days Wks Mos

0 1 1-3 1-4 4-8 8-12 4 4-24 24+

Source 1

Raw or source water and terminal reservoirs 90%

Raw water conveyance (pump stations and 

piping to WTP) 90% X

Potable water at supply (WTP, wells, 

impoundment) 30% 60% 90% X

Water for fire suppression at key supply points 

(to promote redundancy) 90% X

Transmission (including Booster Stations) 1

Backbone transmission facilities (pipelines, 

pump stations, and tanks) 90% X

Control Systems

SCADA or other control systems 30% 60% 90% X

Distribution

Critical Facilities 1

Wholesale Users (other communities, rural 

water districts) 60% 90%

Hospitals, EOC, Police Station, Fire Stations 60% 90% X

Emergency Housing 1

Emergency Shelters 60% 90% X

Housing/Neighborhoods 2

Drink water available at community 

distribution centers 60% 90%

Water for fire suppression at fire hydrants 90% X

Community Recovery Infrastructure 3

All other clusters 30% 90% X

538 Footnotes: See Table 9-2, page 16.
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539 Table 9-4: Example Water Infrastructure Performance Goals for Extreme Event in Centerville, USA

Disturbance Restoration times

(1) Hazard Any (2) 30% Restored

Affected Area for Extreme Event Regional 60% Restored

Disruption Level Severe 90% Restored

(3) X Current

540

Functional Category: Cluster

(4) 

Support 

Needed

(5) 

Target 

Goal

Overall Recovery Time for Hazard and Level Listed

Extreme Hazard Level

Phase 1 – ShortTermPhase 2 –

Intermediate Phase 3 – Long-Term

Days Wks Mos

0 1 1-3 1-4 4-8 8-12 4 4-36 36+

Source 1

Raw or source water and terminal 

reservoirs 30% 60% 90% X

Raw water conveyance (pump stations 

and piping to WTP) 60% 90% X

Potable water at supply (WTP, wells, 

impoundment) 30% 60% 90% X

Water for fire suppression at key supply 

points (to promote redundancy) 90% X

Transmission (including Booster 

Stations) 1

Backbone transmission facilities 

(pipelines, pump stations, and tanks) 30% 60% 90% X

Control Systems

SCADA or other control systems 30% 60% 90%

Distribution

Critical Facilities 1

Wholesale Users (other communities, 

rural water districts) 60% 90% X

Hospitals, EOC, Police Station, Fire 

Stations 60% 90% X

Emergency Housing 1

Emergency Shelters 60% 90% X

Housing/Neighborhoods 2

Drink water available at community 

distribution centers 30% 60% 90% X

Water for fire suppression at fire 

hydrants 60% 90% X

Community Recovery Infrastructure 3

All other clusters 60% 90% X

541 Footnotes: See Table 9-2, page 16.
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542 Table 9-5. Example Wastewater Infrastructure Performance Goals for Routine Event in Centerville, 

543 USA 

Disturbance Restoration times

(1) Hazard Any (2) 30% Restored

Affected Area for Routine Event Localized 60% Restored

Disruption Level Minor 90% Restored

(3) X Current

544

Functional Category: Cluster

(4) 

Support 

Needed

(5) 

Target 

Goal

Overall Recovery Time for Hazard and Level Listed

Routine Hazard Level

Phase 1 – ShortTermPhase 2 --

Intermediate

Phase 3 – LongTerm

Days Wks Mos

0 1 1-3 1-4 4-8 8-12 4 4-24 24+

Treatment Plants

Treatment plants operating with primary treatment 

and disinfection 90% X

Treatment plants operating to meet regulatory 

requirements 90% X

Trunk Lines

Backbone collection facilities (major trunkline, lift 

stations, siphons, relief mains, aerial crossings) 60% 90% X

Flow equalization basins 60% 90% X

Control Systems

SCADA and other control systems 90% X

Collection Lines

Critical Facilities 

Hospitals, EOC, Police Station, Fire Stations 90% X

Emergency Housing

Emergency Shelters 90% X

Housing/Neighborhoods

Threats to public health and safety controlled by 

containing & routing raw sewage away from public 60% 90% X

Community Recovery Infrastructure 

All other clusters 60% 90% X

545 Footnotes: See Table 9-2, page 16.
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546 Table 9-6: Example Wastewater Infrastructure Performance Goals for Expected Event in Centerville, 

547 USA

Disturbance Restoration times

(1) Hazard Any (2) 30% Restored

Affected Area for Expected Event Community 60% Restored

Disruption Level Moderate 90% Restored

(3) X Current

548

Functional Category: Cluster

(4) 

Support 

Needed

(5) 

Target 

Goal

Overall Recovery Time for Hazard and Level Listed

Expected Hazard Level

Phase 1 – ShortTermPhase 2 --

Intermediate

Phase 3 – LongTerm

Days Wks Mos

0 1 1-3 1-4 4-8 8-12 4 4-24 24+

Treatment Plants

Treatment plants operating with primary 

treatment and disinfection 60% 90%

Treatment plants operating to meet regulatory 

requirements 30% 60% 90% X

Trunk Lines

Backbone collection facilities (major trunkline, 

lift stations, siphons, relief mains, aerial 

crossings)

30% 60% 90% X

Flow equalization basins 30% 60% 90% X

Control Systems

SCADA and other control systems 30% 60% 90% X

Collection Lines

Critical Facilities 

Hospitals, EOC, Police Station, Fire Stations 30% 90% X

Emergency Housing

Emergency Shelters 30% 90% X

Housing/Neighborhoods

Threats to public health and safety controlled 

by containing & routing raw sewage away 

from public

30% 60% 90% X

Community Recovery Infrastructure 

All other clusters 30% 60% 90% X

549 Footnotes: See Table 9-2, page 16.
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550 Table 9-7: Example Wastewater Infrastructure Performance Goals for Extreme Event in Centerville, 

551 USA

Disturbance Restoration times

(1) Hazard Any (2) 30% Restored

Affected Area for Extreme Event Regional 60% Restored

Disruption Level Severe 90% Restored

(3) X Current

552

Functional Category: Cluster

(4) 

Support 

Needed

(5) 

Target 

Goal

Overall Recovery Time for Hazard and Level Listed

Extreme Hazard Level

Phase 1 –

Short-Term

Phase 2 --

Intermediate

Phase 3 – LongTerm

Days Wks Mos

0 1

1-

3

1-4 4-8 8-12 4 4-36 36+

Treatment Plants

Treatment plants operating with primary treatment 

and disinfection 30% 60% 90% X

Treatment plants operating to meet regulatory 

requirements 90% X

Trunk Lines

Backbone collection facilities (major trunkline, lift 

stations, siphons, relief mains, aerial crossings) 30% 60% 90% X

Flow equalization basins 30% 60% 90% X

Control Systems

SCADA and other control systems 60% 90% X

Collection Lines

Critical Facilities 

Hospitals, EOC, Police Station, Fire Stations 30% 90% X

Emergency Housing

Emergency Shelters 30% 90% X

Housing/Neighborhoods

Threats to public health and safety controlled by 

containing & routing raw sewage away from public 30% 60% 90% X

Community Recovery Infrastructure 

All other clusters 60% 90% X

553 Footnotes: See Table 9-2, page 16.
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Water and Wastewater Systems, Regulatory Environment

Chapter 9, Page 22 of 32

554 9.4. Regulatory Environment

555 9.4.1. Federal

556 The federal EPA has requirements for drinking water quality defined in the Safe Drinking Water Act and 

557 wastewater discharge water quality defined in the Clean Water Act. These acts are amended on an 

558 ongoing basis. In most cases, the EPA gives states primacy to enforce these requirements. There are 

559 certain prescriptive requirements associated with each. 

560 SDWA Example Requirements

561  Filtration of surface water supplies, except in some cases special treatment of particularly clean 

562 surface water supplies

563  Disinfection of supplies (except a few groundwater supplies)

564  Covering of treated water storage

565 Clean Water Act Example Requirements

566  Secondary treatment of wastewater discharges

567  Disinfection of wastewater discharges

568 In general, these regulations all focus on water quality and have limited interest in catastrophic hazard 

569 event impacts and planning. 

570 9.4.2. State 

571 State Drinking Water Programs. States typically regulate water quality and require treatment approaches 

572 for recycled water. States ensure water systems meet Safe Drinking Water Act standards by ensuring

573 water systems test for contaminants, reviewing plans for water system improvements, conducting on-site 

574 inspections and sanitary surveys, providing training and technical assistance, and taking action against 

575 non-compliant water systems.

576 State Water Quality Programs. States also ensure water systems meet Clean Water Act water quality 

577 standards using state water quality programs. They develop and implement water quality standards, 

578 regulate sewage treatment systems and industrial dischargers, collect and evaluate water quality data, 

579 provide training and technical assistance, and take action against non-compliant wastewater systems.

580 Emergency Planning and Community Right-to-Know Act (EPCRA). Facilities that store, use, or release 

581 certain chemicals may be subject to reporting requirements to state and/or local agencies through EPCRA. 

582 Information in reports then becomes publically available. Treatment chemicals stored and used at water 

583 treatment plants often require this type of reporting.

584 Planning Requirements. Water and wastewater planning and design requirements are generally 

585 controlled by states and local governments. States typically require comprehensive plans for water and 

586 wastewater system are prepared on a regular basis to assess future system needs (e.g. capacity) and how 

587 those needs will be met. The elements of those comprehensive plans are defined by the state. Often times, 

588 these plans include requirements to identify hazards to which the system could be subjected, and how the 

589 utility will address those hazards. These are typically quite general in nature and do not include detailed 

590 design criteria.

591 9.4.3. Local

592 Individual municipalities or utility districts may elect to impose regulatory standards in excess of federal 

593 and state standards. In practice, this is seldom done due to the increased cost to customers associated with 

594 meeting higher-than-minimum regulatory standards.
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595 9.5. Standards and Codes

596 The state and local government are responsible for adopting model building codes, such as the 

597 International Building Code (IBC). Model building codes rely heavily on standards, such ASCE-7, 

598 Minimum Design Loads for Buildings and Other Structures. In many cases, the state will adopt these

599 model codes; in some cases, local jurisdictions modify them to suit their needs. The IBC and ASCE-7 

600 focus on building structure life safety. State and local agencies will also have special requirements for 

601 high risk facilities, such as dams. The Federal Energy Regulatory Commission controls designs of 

602 hydroelectric generating dams.

603 The development of design codes is a long and arduous process. Theses codes are updated on a regular 

604 basis taking into account performance of facilities since the last code was issued and other developments 

605 in the building industry. Once they are finalized, they are voted on by the code committee and finally 

606 adopted by state and/or local jurisdictions. Once a code is well vetted, the state and local jurisdictions 

607 adopt it.

608 The following subsections discuss some of the codes, standards, and guidelines that are important to the 

609 disaster resilience of water and wastewater infrastructure, the anticipated performance of the 

610 infrastructure after an expected hazard event, and the long-term recovery levels of the infrastructure when 

611 damage does occur. 

612 9.5.1. New Construction

613 Design Standards. Developed and adopted by various organizations, the two organizations that have 

614 standards most relevant to natural hazard impacts on the water and wastewater industry include:

615  American Concrete Institute – standards addressing concrete process tanks (ACI 350)

616  American Water Works Association (AWWA) –

617  Standards addressing design of water storage tanks (AWWA D100, D110, D115), addressing 

618 seismic design of water storage tanks

619  Standard AWWA-J100, Risk and Resilience Management of Water and Wastewater Systems, 

620 addressing performance of water and wastewater systems when subjected to natural and 

621 manmade hazards

622 AWWA has other standards addressing pipeline design and water quality. However, none of these other 

623 standards addresses seismic design for other natural hazards.

624 For the design of new underground pipelines, there is not a unifying code for water and wastewater 

625 systems. This is especially true for seismic design of buried water and wastewater pipelines or buried 

626 pipelines that may be impacted by landslides induced by flooding. Often the Chief Engineer of a 

627 particular utility is responsible for establishing its design practices. While these agency-specific design 

628 practices are generally based on industry recommendations, variability in standards used by utilities 

629 results in variability in the intended system reliability for natural and man-made hazards.

630 Some utilities develop their own standards to address significant local hazards specifically. For example, 

631 the San Francisco Public Utilities Commission (SFPUC) developed its own internal standard that outlines 

632 level of service performance goals following a major Bay Area earthquake and specific requirements for

633 design and retrofit of aboveground and underground infrastructure. The SFPUC Engineering Standard 

634 General Seismic Requirements for Design of New Facilities and Upgrade of Existing Facilities (SFPUC, 

635 2006) establishes design criteria that in many cases are more stringent than building codes and/or industry 

636 standards, yet ensures the SFPUC achieves its basic level of service performance goal to deliver winter 

637 day demand to their wholesale customers within 24 hours after a major earthquake.

638 Guidelines and Manuals of Practice. A number of organizations have developed guidelines intended for 

639 use by the industry to enhance design of the particular product being addressed. Table 9-8 lists some of 

640 the model codes, standards, and guidance documents applicable to water and wastewater infrastructure. 
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641 This table also shows a matrix of system component to document. This list is not intended to be 

642 exhaustive. However, the reader should be aware of these documents that pertain to disaster resilience. 

643 Table 9-8. Codes, Standards, and Guidelines for Hazard Resistance of Water and Wastewater Facilities

Org Category 

(1) Name

GeneralPipelinesPumpingStorageTreatment

IBC C 2012 International Building Code or applicable jurisdictional building code x

ASCE S Minimum Design Loads for Buildings and Other Structures x

ACI S 350 Code Requirements for Environmental Engineering Concrete Structures x x

ACI S 371R-08 Guide for the Analysis, Design, and Construction of Elevated 

Concrete and Composite Steel-Concrete Water Storage Tanks

x

ACI S 372R-03 Design and Construction of Circular Wire- and Strand-Wrapped 

Prestressed Concrete Structures

x x

AWWA S D100-11 Welded Carbon Steel Tanks for Water Storage x

AWWA S D110-13 Wire- and Strand-Wound, Circular, Prestressed Concrete Tanks x

AWWA S D115-06 Tendon-Prestressed Concrete Water Tanks x

AWWA S G430-14 Security Practices for Operation and Management x

AWWA S J100-10 Risk Analysis and Management for Critical Asset Protection Standard 

for Risk and Resilience Management of Water and Wastewater Systems

x

AWWA S G440-11 Emergency Preparedness Practices x

ALA G Guidelines for Implementing Performance Assessments of Water Systems x

ALA G Guidelines for the Design of Buried Steel Pipe (2001) x

ALA G Seismic Design and Retrofit of Piping Systems (2002) x x

ALA G Seismic Fragility Formulations for Water Systems (2001) x

ALA G Seismic Guidelines for Water Pipelines (2005) x

ALA G Wastewater System Performance Assessment Guideline (2004) x

ASCE G Guidelines for Seismic Design of Oil and Gas Pipeline Systems (1984) x

AWWA G Emergency Power Source Planning for Water and Wastewater x

AWWA G M9 Concrete Pressure Pipe x

AWWA G M11 Steel Pipe: A Guide for Design and Installation x

AWWA G M19 Emergency Planning for Water Utilities x

AWWA G M60 Drought Preparedness and Response x

AWWA G Minimizing Earthquake Damage, A Guide for Water Utilities (1994) x

EPA/AWWA G Planning for an Emergency Drinking Water Supply x

MCEER G MCEER-08-0009 Fragility Analysis of Water Supply Systems (2008) x

MCEER G Monograph Series No. 3 Response of Buried Pipelines Subject to Earthquakes x

MCEER G Monograph Series No. 4 Seismic Design of Buried and Offshore Pipelines x

TCLEE G Monograph 15 Guidelines for the Seismic Evaluation and Upgrade of Water 

Transmission Facilities (1999)

x

TCLEE G Monograph 22 Seismic Screening Checklists for Water and Wastewater 

Facilities (2002)

x

WEF G Emergency Planning, Response, and Recovery x

WEF G Guide for Municipal Wet Weather Strategies x

WEF G MOP 28 Upgrading and Retrofitting Water and Wastewater Treatment Plants x

WEF G MOP 8 Design of Municipal Wastewater Treatment Plants x

WEF G MOP FD-17 Prevention and Control of Sewer System Overflows x

644 C – Code; S – Standard; G – Guideline or Manual of Practice (MOP)

645 9.5.1.1. Implied or Stated Performance Levels for Expected Hazard Levels

646 Design of new aboveground structures (i.e., treatment plant office and lab buildings, pump stations, 

647 process tanks, water storage tanks and reservoirs, etc.) is typically governed by local building codes or 

648 design standards that prescribe a similar wind, seismic, or other hazard as the local building code. Design 
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649 loads are prescribed by a consensus-based standard, Minimum Design Loads for Buildings and Other 

650 Structures (ASCE, 2010). This standard uses the concept of Risk Category to increase the design force 

651 level for important structures. Typical buildings are assigned to Risk Category II. Water and wastewater 

652 treatment facilities are assigned to Risk Category III, because failure of these facilities can cause 

653 disruption to civilian life and potentially cause public health risks. Water storage facilities and pump 

654 stations required to maintain water pressure for fire suppression are assigned to the highest category, Risk 

655 Category IV. 

656 The building code intends that structures designed as Risk Category III or IV should remain operational 

657 or require only minor repairs to be put back into operation following a design level (expected) wind, 

658 seismic, or other event. By designing for this performance target for the expected level event, water and 

659 wastewater systems should remain operational under a routine level event and may experience moderate 

660 to major damage during an extreme level event.

661 The performance level implied by codes and standards for new construction provides an indication of the 

662 recovery level (timeframe) expected for individual system components. The timeframe required for water 

663 or wastewater systems to return to normal operating status following a hazard event is highly dependent 

664 on the recovery time for individual system components and the system’s specific characteristics (e.g., 

665 type and number of components, age of construction, system redundancy, etc.). Estimating system 

666 recovery times for a specific hazard requires in-depth engineering and operational knowledge of the 

667 system. 

668 Table 9-9 summarizes water and wastewater system component performance and recovery levels for 

669 earthquake hazard levels as implied by current codes and standards for new construction. Predicted 

670 recovery times are based on individual system components.

671 Table 9-9. Water and Wastewater System Component Performance and Recovery Levels for Various 

672 Earthquake Hazard Levels as Implied by Current Codes and Standards for New Construction

System Component Hazard Level Performance Level Recovery Level

Structures (pump 

stations, treatment 

plants, office/lab 

buildings, tanks, 

reservoirs, etc.)

Routine (50 year return period 

earthquake)

Safe and operational Resume 100% service within days

Expected (500 year return 

period earthquake)

Risk Category III (I=1.25) – Safe and 

usable during repair

Resume 100% service within 

months

Risk Category IV (I=1.5) – Safe and 

operational

Resume 100% service within days

Extreme (2500 year return 

period earthquake)

Risk Category III (I=1.25) – Safe and not 

usable

Resume 100% service within 

years

Risk Category IV (I=1.5) – Safe and usable 

during repair or not usable

Resume 100% service within 

months to years

Nonstructural 

components (process, 

lab, mechanical, 

electrical, and plumbing 

equipment, etc.)

Routine (50 year return period 

earthquake)

Safe and operational Resume 100% service within days

Expected (500 year return 

period earthquake)

Risk Category III (I=1.25) – Safe and 

usable during repair

Resume 100% service within 

months

Risk Category IV (I=1.5) – Safe and 

operational

Resume 100% service within days

Extreme (2500 year return 

period earthquake)

Risk Category III (I=1.25) – Safe and not 

usable

Resume 100% service within 

years

Risk Category IV (I=1.5) – Safe and usable 

during repair or not usable

Resume 100% service within 

months to years

Pipelines Routine (50 year return period 

earthquake)

Operational Resume 100% service within days

Expected (500 year return 

period earthquake)

Operational to not usable Resume 100% service within 

months

Extreme (2500 year return 

period earthquake)

Not usable Resume 100% service within 

years
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673 9.5.2. Existing Construction

674 9.5.2.1. Implied or Stated Performance Levels for Expected Hazard Levels

675 The design seismic hazard level was refined over time as the engineering and seismology community’s 

676 understanding of United States seismicity improved. A significant portion of water and wastewater 

677 system components in the high seismicity regions of the western and central United States were designed 

678 and constructed considering a significantly lower seismic hazard than the hazard used by current codes 

679 and standards.

680 Expected seismic performance of water and wastewater system components is dependent on the hazard 

681 level, codes and standards used in original design, and the type of structure. System components built 

682 prior to the mid-1970s are generally expected to perform poorly in earthquakes, because design codes and 

683 standards used at that time lacked the detailed requirements that reflect our current understanding of 

684 structures’ behaviors during earthquakes. System components built after the early 2000s are generally 

685 expected to perform similar to new construction as described above. Performance of system components 

686 built between the mid-1970s and early 2000s is dependent on the code edition and seismic hazard used in 

687 design. Structures that satisfy the benchmark building criteria of ASCE 41-13 (ASCE, 2013) and are in 

688 areas that haven’t experienced a significant increase in seismicity are generally expected to perform 

689 similar to new construction as described above. However, some types of structures are inherently rugged. 

690 For example, many older cast-in-place concrete structures, particularly single story buildings with few 

691 opening would be expected to perform well.

692 Anticipated performance of nonstructural components should be evaluated on a case-by-case basis, as 

693 engineers now pay closer attention to seismic design and construction of nonstructural components. 

694 Anticipated performance of pipelines should be evaluated on a system-by-system basis because 

695 performance of pipelines is dependent on pipe type, joint type, and earthquake ground movement 

696 parameters. Even today, there is no code or standard for seismic design of pipelines.

697 9.5.2.2. Recovery Levels

698 In the past, infrastructure systems have not performed to the level that communities would desire with

699 extended recovery times beyond the example performance goals in Section 9.3. There are a number of 

700 examples of disaster events that have rendered utilities non-functional for weeks following the event and 

701 illustrate importance of considering the interdependencies of water and wastewater systems with other 

702 systems of the built environment. A few notable events and their actual recover levels are discussed 

703 herein.

704 Great Flood of 1993. In the Great Flood of 1993, the Raccoon River overtopped its banks and submerged 

705 the Des Moines, Iowa WWTP. The water receded and the plant was able to restore non-potable water 

706 within 12 days and potable water within 19 days. The water outage disrupted restaurant and hotel 

707 operations. The Principal Insurance Company headquarters had to haul in water and pump it into the 

708 building to cool computers. AT&T’s regional central office came within minutes of losing phone service 

709 because of computer cooling issues.

710 Northridge and Kobe Earthquakes. In the 1994 Northridge earthquake, the Los Angeles Department of 

711 Water and Power’s distribution system suffered approximately 1,000 pipeline failures, primarily in the 

712 San Fernando Valley. With their own forces and mutual aid, they were able to fully restore potable water 

713 service to everyone within 12 days. A year later, the 1995 Kobe Japan earthquake suffered 1,200 pipeline 

714 failures resulting in lost service to all households for up to 60 days.

715 Christchurch, New Zealand and Tohoku, Japan Earthquakes. The recent 2011 Christchurch New 

716 Zealand, and Tohoku Japan earthquakes both resulted in outages lasting in excess of 40 days. Impacted 

717 Japanese cities were assisted by mutual aid from their colleagues from cities in western Japan.
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718 9.6. Strategies for Implementing Community Resilience Plans

719 Section 9.2 discusses components of water and wastewater infrastructure system. The discussion includes 

720 examples from different types of hazards to encourage the reader to think about the different hazards that 

721 could impact the communication and information infrastructure in their community. The number, types, 

722 and magnitudes of hazards that need to be considered will vary from community to community. 

723 Section 9.3 discusses example performance goals for the water and wastewater infrastructure system in 

724 fictional town Centerville, USA. These example performance goals are provided for the routine, expected 

725 and extreme event. However, the performance goals should be adjusted by the community based on its 

726 social needs.

727 Section 9.4 and 9.5 outline some of the regulatory levels and issues, and codes and standards that the 

728 reader should keep in mind when planning to make upgrades/changes to existing infrastructure as well as 

729 building new structures for their water and wastewater infrastructure system. The objective of this section 

730 is use the information from Sections 9.2 through 9.5 to provide guidance on how a community should 

731 work through the process of assessing their communications infrastructure, defining strategies to make its 

732 infrastructure more resilient, and narrowing the resilience gaps. 

733 9.6.1. Available Guidance

734 The purpose of the assessment is to quantify the anticipated performance and recovery of the overall 

735 system to determine whether it meets the performance goals described in Section 9.3. If the system does 

736 not meet the objectives, the assessment should identify system facility and pipe deficiencies that should 

737 be improved to achieve those performance goals. 

738 Section 9.2.1 describes the basic components of water and wastewater systems and observations of where 

739 these systems failed in past disasters. System performance is also highly dependent on the current 

740 condition of the system and standards used in its design. Information about past disaster performance of 

741 similar systems combined with knowledge of current condition and original design standards of the 

742 system help a utility estimate the expected level of service they could provide after a hazard event. There 

743 is likely a gap in the level of service a system would provide if a hazard event occurred today versus 

744 community-established performance goals. It is likely that the capital expenditure required to close this 

745 performance gap far exceeds the short-term capital improvement project budgets of the utility. However, 

746 the resilience of any system can be improved incrementally over time by appropriately considering design 

747 criteria to reduce the impact of natural and man-made hazards in designing new and upgrading existing 

748 infrastructure. To estimate the level of service a water or wastewater system would provide after a given 

749 scenario hazard event, an assessment of expected damage to the system and restoration times is required. 

750 The level of detail of this assessment can take one of three basic forms. 

751  Tier 1 – A high-level assessment of hazards and their performance conducted by persons 

752 knowledgeable about the system (chief engineer, operations manager, etc.). This can be 

753 accomplished in a workshop setting using system maps and schematics, along with hazard maps 

754 of the service area, such as liquefaction susceptibility or flood plain maps. Restoration times will 

755 be based on professional judgment of the workshop participants.

756  Tier 2 – A more refined assessment based on published scenario events and hazard zones, system 

757 inventory (i.e., facility type, age, condition, and location relative to hazards, and pipe type, length 

758 and soil type), site visits, and use of generalized component fragilities, such as those included in 

759 HAZUS-MH and ALA documents. Restoration times are based on the extent of damage (e.g., 

760 number of pipeline breaks), estimates of the time to repair each category of damage, and crews 

761 and equipment available for restoration.

762  Tier 3 – A detailed assessment of all components in a system, specific component fragilities, and 

763 the interdependencies of system components. Same as Tier 2, with the addition of detailed 
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764 analysis (e.g. geotechnical, structural or hydraulic) of facilities and pipelines determined to be 

765 vulnerable and critical, should they fail, significantly impacting the overall system operation.

766 To characterize the current disaster resilience of water and wastewater systems appropriately, each service 

767 provider should undergo a Tier 1 assessment. If potential resilience vulnerabilities are identified, they 

768 should undergo a more refined Tier 2 or 3 assessment. Several methodologies and tools are available to 

769 conduct these resilience assessments, a few of which are described below.

770 HAZUS-MH is a multi-hazard (flood, earthquake, and hurricane) loss estimation tool developed by the 

771 Federal Emergency Management Agency (FEMA) for use in pre-disaster mitigation, emergency 

772 preparedness, and response and recovery planning (FEMA, 2012). Communities can use this tool to 

773 characterize their hazard exposure, estimate losses to the water and wastewater systems, and estimate 

774 repair costs and duration. It assists in conducting a Tier 2 analysis and an AWWA J100 analysis as 

775 discussed below.

776 The ANSI/AWWA J100-10 Standard for Risk and Resilience Management of Water and Wastewater 

777 Systems (AWWA, 2010) provides a methodology for conducting multi-hazard system risk and resilience

778 assessments. The J100 aligns the national homeland security objectives in HSPD-5, PPD-8, PPD-21 and 

779 EO 13636. The J100 standard consists of a seven-step process for analyzing and supporting management 

780 decisions that maximize risk reduction and/or enhance resilience at the utility and the community it 

781 serves.

782 1. Asset Characterization

783 2. Threat Characterization

784 3. Consequence Analysis

785 4. Vulnerability Analysis

786 5. Threat Analysis

787 6. Risk/Resilience Analysis

788 7. Risk/Resilience Management

789 Asset level resilience for specific threats is part of the J100 assessment methodology, which may support 

790 a community’s process for determining current performance and target performance (Section 9.3). The

791 J100 also includes the Utility Resilience Index (URI), which is a system-level assessment of operational 

792 and financial indicators that are essential to resilience and, therefore, an asset’s ability to effectively serve 

793 a community. The URI serves as a benchmark to evaluate potential resilience improvement projects and 

794 as a measure to track a utility’s progress over time towards achieving resilience performance goals.

795 Several tools were developed by the U.S. Environmental Protection Agency to support the water utility 

796 assessment of risks. The Vulnerability Self-Assessment Tool (VSAT) (EPA 2014) is designed to assist 

797 water and wastewater utilities’ application of the J100 standard. VSAT is complemented by the Water 

798 Health and Economic Analysis Tool (WHEAT), which quantifies three aspects of consequence associated 

799 with an adverse event’s 1) public health impact, 2) utility-level financial impact, and 3) direct and indirect 

800 regional economic impact (EPA, 2014). WHEAT is specifically aligned with step 3 (consequence 

801 analysis) of J100 standard. 

802 The EPA’s National Homeland Security Research Center (NHSRC) also supported efforts to enhance 

803 utility resilience. Collaboration with AWWA resulted in the development of Planning for an Emergency 

804 Drinking Water Supply, which directly supports a capability assessment based on worst reasonable threats 

805 in J100 to determine options for maintaining service.

806 An example Tier 2 resilience assessment procedure for water systems is outlined in the following.

807 9.6.1.1. Example Tier 2 Resilience Assessment for Earthquake:

808 1. Identify the appropriate earthquake scenario or scenarios. Develop or obtain ground motion 

809 information for each. The USGS has scenarios available for a suite of earthquakes in the U.S. 
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810 Obtain liquefaction and landslide hazard maps available from the state department of geology. 

811 Use GIS for all mapping.

812 For buried pipelines:

813 2. Compile an inventory of system pipelines including pipe material, joint type, and length.

814 3. In GIS, superimpose the pipeline distribution system onto maps of the scenario hazard (peak 

815 ground velocity, liquefaction potential, and landslide potential). 

816 4. Use empirical relationships developed by the American Lifelines Alliance (ALA) to predict the 

817 number of breaks and leaks in the pipeline system. 

818 5. Estimate the time required to repair the predicted number of breaks and leaks based on historical 

819 crew productivity data. Modify this repair time, as appropriate, based on discussions of the 

820 expected damage states of interdependent lifelines (transportation, liquid fuel, etc.).

821 For aboveground infrastructure:

822 6. Compile an inventory of system components (tanks, pump stations, treatment plants, etc.), 

823 including type of construction, date of original construction, and any subsequent retrofits.

824 7. Estimate the level of damage predicted for the aboveground water system components based on 

825 observations from past earthquakes, the seismic hazard prescribed by the building code at the 

826 time of original construction or retrofit, and the professional judgment of engineers 

827 knowledgeable in the seismic performance of water systems. Use fragility curves found in 

828 HAZUS-MH to determine the anticipated performance for a particular facility type for a given 

829 ground motion.

830 8. Estimate the time required to repair the predicted damage to aboveground infrastructure. Modify 

831 this repair time, as appropriate, based on discussions of the expected damage states of 

832 interdependent lifelines (transportation, liquid fuel, etc.)

833 For the system:

834 9. Determine the expected system performance based on the damage to pipelines and facilities in a 

835 workshop format.

836 10. Determine the expected repair time for the system based on the repair times for buried pipelines 

837 and aboveground infrastructure estimated in steps 5 and 8.

838 11. Compare this estimate of repair time for the system to the performance goals established by the 

839 community to determine the resilience gap.

840 These different resilience assessment approaches should be evaluated and refined into one consistent 

841 methodology prior to implementation of nationwide water and wastewater system resilience assessments. 

842 The tier level of the assessment increases by conducting detailed analyses of each facility and pipeline. 

843 Note that recovery time for utilities that purchase water from wholesale suppliers is highly dependent on 

844 the recovery time of the supplying utility. Wholesale water suppliers should work with their customers to 

845 assess the expected damage and restorations times from the source to the final individual customers. In 

846 this case, water and wastewater system resilience assessments may require a regional approach to 

847 characterize the anticipated performance of the system of systems in a hazard event appropriately.

848 9.6.2. Strategies for New Construction

849 Water and wastewater providers should consider resilience performance goals in all new construction 

850 projects. Projects should be designed to satisfy or exceed code requirements, where code minimum 

851 standards are not anticipated to provide a final product that would be expected to meet the utility’s 

852 resilience performance goals. If no codes exist for a particular category of structure or facility, the 

853 designer should investigate guidelines that address hazard-resistant design issues (see Table 9.4). The 

854 incremental cost of designing and constructing for improved disaster resilience may be a relatively small 

855 percentage of total project costs. 
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856 9.6.3. Strategies for Existing Construction

857 Water and wastewater providers should consider resilience improvements to existing infrastructure as part 

858 of the capital improvement planning process. The process of conducting system resilience assessments 

859 will likely identify key pipelines and facilities that significantly impact the overall resilience of a system. 

860 These components should be evaluated in detail. Providers should evaluate a number of potential 

861 strategies, including retrofit or replacement of existing components, or building redundant components in 

862 anticipation of failure of existing components. Retrofit of existing infrastructure or new redundant 

863 components should be designed such that the final product would be expected to meet the utility’s 

864 resilience performance goals. In some cases, redundant systems can be justified based on increasing 

865 demand requirements. The “new” redundant system could provide on its own an adequate supply to meet 

866 an average day’s demand until the damaged system was repaired. Whatever is done needs to be part of the 

867 day-to-day needs of the utility. That is, if special features added to a system to increase resilience are 

868 never used, there is a high likelihood they will not be functional when they are needed.

869 Once water and wastewater providers and the community establish resilience performance goals and 

870 complete baseline resilience assessments, there may be a number of goals not currently met due to the 

871 anticipated performance of system components, financial resources of the utility, interdependencies with 

872 other lifelines, etc. These performance gaps are likely to be addressed by a phased program (perhaps over 

873 as long as a 50-year period) of new construction, retrofit of existing system components to better 

874 withstand hazard events, modifications to emergency response plans, coordination with interdependent 

875 lifeline providers, and other strategies. It is expected that these resilience enhancements will be coupled 

876 with other system improvements to maximize the benefit of limited financial resources. 

877 For instance, it can be difficult to justify replacing hundreds of miles of water pipelines based on 

878 earthquake resilience considerations alone, but coupled with replacement of aging and failing pipelines, 

879 the incremental cost of using more earthquake-resistant pipe materials and joints is relatively minor. 

880 Major resilience improvements that take place on a shorter timeline require a more extensive campaign of 

881 public outreach and education. 

882 9.7. References

883 Allouche, E.N., Sterline, R.L., Chisolm, E., Hill, D., and Hall, D. (2006). Assessment of Damage to 

884 Urban Buried Infrastructure in the Aftermath of Hurricanes Katrina and Rita. Proceedings 

885 Pipelines 2006: Service to the Owner. ASCE.

886 ASCE (2013). Seismic Evaluation and Rehabilitation of Existing Buildings. Reston, VA: American 

887 Society of Civil Engineers.

888 Aubuchon, C.P., & Morley, Kevin (2012). The Economic Value of Water: Providing Confidence and 

889 Context to FEMA’s Methodology. Journal of Homeland Security and Emergency Management, 

890 10(1), 2194-6361.

891 AWWA (1994). Minimizing Earthquake Damage, A Guide for Water Utilities. Denver, CO: American 

892 Water Works Association.

893 AWWA (2001). M19 Emergency Planning for Water Utilities. Denver, CO: American Water Works 

894 Association.

895 AWWA (2004). Emergency Power Source Planning for Water and Wastewater. Denver, CO: American 

896 Water Works Association.

897 AWWA (2010). ANSI/AWWA J100-10 Risk and Resilience Management of Water and Wastewater 

898 Systems. Denver, CO: American Water Works Association.

899 AWWA (2011). ANSI/AWWA G440-11 Emergency Preparedness Practices. Denver, CO: American 

900 Water Works Association.
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901 AWWA (2014). ANSI/AWWA G430-14 Security Practices for Operation and Management. Denver, CO: 

902 American Water Works Association.

903 Ballantyne, D., & Crouse, C. (1997). Reliability and Restoration of Water Supply Systems for Fire 

904 Suppression and Drinking Following Earthquakes. Gaithersburg, MD: National Institute of 

905 Standards and Technology.

906 Chisolm, E. & Matthews, J. (2012). Impact of Hurricanes and Flooding on Buried Infrastructure. 

907 Leadership and Management in Engineering. July 2012. Vol. 12, Issue 3. 

908 Eidinger, J. (2012). Performance of Water Systems during the Maule Mw 8.8 Earthquake 27 February 

909 2010. Earthquake Spectra, Vol. 28, No. S1, S605-S620.

910 Eidinger, J., & Tang, A. (2014). Christchurch, New Zealand Earthqake Sequence of Mw 7.1 September 

911 04, 2010 Mw 6.3 February 22, 2011 Mw 6.0 June 13, 2011: Lifeline Performance. Reston, VA: 

912 American Society of Civil Engineers.

913 Elliott, T., & Tang, A. (2009). Pacific Northwest Storms of December 1-4, 2007 Lifeline Performance.

914 Reston, VA: American Society of Civil Engineers.

915 EPA (2010). VSAT – Risk Assessment Tool for Water Sector Utilities. Washington, D.C.: Environmental 

916 Protection Agency.

917 EPA (2014). Water Health and Economic Analysis Tool Version 3.0, Consequence Analysis Tool for 

918 Water Utilities. Washington, D.C.: Environmental Protection Agency.

919 FEMA (2012). Hazus-MH 2.1 User Manual. Washington, D.C.: Federal Emergency Management 

920 Agency.

921 FEMA (2013). Mitigation Assessment Team Report Hurricane Sandy in New Jersey and New York 

922 Building Performance Observations, Recommendations, and Technical Guidance . Washington, 

923 D.C.: Federal Emergency Management Agency.

924 Matsuhashi, M., Fukatani, W., Yokota, T., Ozaki, M., & Horie, N. (2012). The Damage of Sewage 

925 Treatment Systems Caused by the Great East Japan Earthquake. International Symposium on 

926 Engineering Lessons Learned from the 2011 Great East Japan Earthquake, Tokyo, Japan.

927 Miyajima, M. (2012). Damage to Water Supply System Induced by the 2011 Great East Japan 

928 Earthquake. International Symposium on Engineering Lessons Learned from the 2011 Great East 

929 Japan Earthquake, Tokyo, Japan.

930 Morley, Kevin (2013). Correct reference to be provided in next draft.

931 NYCDEP (2013). New York City Wastewater Resiliency Plan: Climate Risk Assessment and Adaptation 

932 Study. October 2013. New York City Department of Environmental Protection.

933 NIST (1996). The January 17, 1995 Hyogoken-Nanbu (Kobe) Earthquake: Performance of Structures, 

934 Lifelines, and Fire Protection Systems. Gaithersburg, MD: National Institute of Standards and 

935 Technology.

936 O’Rourke, T. (2014). Resilient Lifeline Systems, ASCE TCLEE LeVal Lund Lecture, April 2, 2014, 

937 California Institute of Technology, Pasadena, CA.

938 OSSPAC (2013). The Oregon Resilience Plan, Reducing Risk and Improving Recovery for the Next 

939 Cascadia Earthquake and Tsunami. Salem, OR: Oregon Seismic Safety Policy Advisory 

940 Commission.

941 Sanders, D.A. (1997.) Damage to Wastewater Treatment Facilities from Great Flood of 1993. Journal of 

942 Environmental Engineering. January 1997. Vol. 123, Issue 1.
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943 SFPUC (2006). General Seismic Requirements for Design of New Facilities and Upgrade of Existing 

944 Facilities. San Francisco, CA: San Francisco Public Utilities Commission.

945 Schiff, A. (1997). Northridge Earthquake: Lifeline Performance and Post-Earthquake Response.

946 Gaithersburg, MD: National Institute of Standards and Technology.

947 Tang, A., & Edwards, C. (2014). Tohoku, Japan, Earthquake and Tsunami of March 11, 2011 Lifeline 

948 Performance. Reston, VA: American Society of Civil Engineers.