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Draft Program EIS/EIR 3.12 Hydrology and Water Resources

3.12-1

3.12 HYDROLOGY AND WATER RESOURCES

This section addresses the potential impacts of the No Build and Build Alternatives

related to hydrology and water resources. Water resources analyzed include 

floodplains, surface waters, and groundwater.

3.12.1 REGULATORY REQUIREMENTS

Federal

Clean Water Act

The Clean Water Act (CWA) was enacted by Congress in 1972 and subsequently

amended several times. It is the primary federal law regulating water quality in the 

United States, and has formed the basis for several state and local laws throughout 

the country. The key objective of the CWA is to protect water quality by regulating 

pollution in the nation’s rivers, stream, lakes, and coastal waters. The CWA 

prescribed the basic federal laws for regulating discharges of pollutants as well as 

set minimum water quality standards for all “waters of the United States.” The

CWA makes the discharge of pollutants into waters of the United States unlawful 

without a proper permit. 

Several additional mechanisms are employed to control domestic, industrial, and 

agricultural pollution under the CWA. At the federal level, the CWA is administered 

by the U.S. Environmental Protection Agency (EPA). In California, the CWA is 

administered and enforced by the State Water Resources Control Board (SWRCB) 

and the Regional Water Quality Control Boards (RWQCBs). The state of California 

has developed a number of water quality laws, rules, and regulations, in part to 

assist in the implementation of the CWA and related federally mandated water 

quality requirements. In many cases, the federal requirements set minimum 

standards and policies; the laws, rules, and regulations adopted by the state and 

regional boards often exceed the federal requirements. 

Important sections of the CWA include:

 Section 303 and 304: Require states to promulgate water quality standards, 

criteria, and guidelines. Section 303(d) specifically regulates impaired water 

bodies and requires each state to identify waters that will fail to achieve water 

quality standards even after maintaining effluent standards, and to enact 

improvement plans. Each state must develop load-based (rather than 

concentration based) limits called total maximum daily loads (TMDL) for each 
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water body and pollutant for which water quality is considered impaired. It is 

up to the state to prioritize development of TMDLs based on the severity of the 

pollution and the beneficial uses of the water body. 

 Section 401: Requires a federal permit to conduct any activity that may result in 

a discharge to waters of the U.S. The applicant must obtain certification from 

the state that the discharge will comply with other provisions of the act.

 Section 402: Establishes the National Pollutant Discharge Elimination System 

(NPDES), a permitting system for point source discharges (except for dredge or 

fill material) of any pollutant into waters of the United States, as authorized by 

the CWA. RWQCBs administer this permitting program in California. The 

entirety of the Coast Corridor under review here (Salinas to San Luis Obispo) is 

within the Central Coast RWQCB based in San Luis Obispo. Section 402(p) 

requires NPDES permits for discharges of storm water from 

industrial/construction and municipal sources into storm sewer systems. The 

permit ensures the receiving waters will meet water quality standards. 

 Section 404: Establishes a permit program for the discharge of dredge and fill 

materials into waters of the United States. This permit program is administered 

by the U.S. Army Corps of Engineers (USACE). 

Rivers and Harbors Act

Section 10 of the Rivers and Harbors Act prohibits the unauthorized obstruction or 

alteration of any navigable water of the United States. The construction of any 

structure in or over any navigable water of the United States, the excavation from or 

depositing of material in such waters, or the accomplishment of any other work 

affecting the course, location, condition, or capacity of such waters is unlawful 

unless the work has been recommended by the Chief of Engineers and authorized 

by the Secretary of the Army. The instrument of authorization is designated a

Section 10 permit.

Flood Disaster Protection Act

The Flood Disaster Protection Act of 1973 requires flood insurance for the 

protection of property located in Special Flood Hazard Areas (SHFAs). Flood-prone 

areas are identified and flood insurance is provided to residents and businesses in 

those areas.
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Executive Order 11988 

Executive Order 11988 (Floodplain Management) addresses floodplain issues 

related to public safety, conservation, and economics. The Executive Order requires 

federal agencies to avoid short- and long-term impacts resulting from the 

modification and development of floodplains to the maximum extent feasible.

State

Porter-Cologne Water Quality Control Act

The Porter-Cologne Act, enacted in 1969, provides the legal basis for water quality 

regulation within California. The law gives responsibility to the SWRCB and the 

RWQCBs to establish the water quality standards (objectives and beneficial uses) 

required by the CWA. Additionally, the SWRCB and RWQCBs regulate discharges to 

ensure compliance with water quality standards. In California, Regional Boards 

designate the beneficial uses for all water body segments in their jurisdictions, and 

then set criteria necessary to protect these uses. 

California Fish and Game Code, Section 1602

Pursuant to Section 1602 of the California Fish and Game Code, California 

Department of Fish and Wildlife (CDFW) regulates activities that divert, obstruct, or 

alter stream flow, or substantially modify the bed, channel, or bank of a stream, 

which CDFW typically considers to include riparian vegetation. Any proposed 

activity in a natural stream channel that would adversely affect an existing fish 

and/or wildlife resource, would require entering into a Streambed Alteration 

Agreement (SBAA) with CDFW prior to commencing work in the stream. However, 

prior to authorizing such permits, CDFW typically reviews an analysis of the 

expected biological impacts, any proposed mitigation plans that would be 

implemented to offset biological impacts and engineering and erosion control plans.

Local

City of Salinas General Plan

The City of Salina General Plan sets forth policies intended to ensure a safe and 

adequate water supply for community uses and to encourage the conservation of 

water resources. Specific policies aim to maintain and restore natural watersheds 

to recharge the aquifers and ensure the viability of the ground water resources. 

Cooperation with the SWRCB and the RWQCB is encouraged to address poor water 

quality in the area. The General Plan also promotes regional efforts to protect and 

enhance water quality. 
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City of Soledad General Plan

The City of Soledad General Plan sets forth policies requiring projects to allocate 

land as necessary for the purpose of retaining flows and/or for the incorporation of 

mitigation measures for water quality and supply impacts related to runoff. 

Mitigation related to controlling pollutant loads in urban storm water runoff must 

be coordinated with responsible agencies, such as the RWQCB.

City of King (King City) General Plan

The City’s General Plan includes goals and policies assuring groundwater resources 

are available to the city and that their quality is not degraded. Specific policies aim 

to preserve and protect all groundwater recharge areas from sources of pollution, 

and to regulate development in such areas to ensure that recharge capabilities are 

not significantly diminished. 

City of El Paso de Robles (Paso Robles) General Plan

The City of El Paso de Robles General Plan contains goals and policies aiming to 

ensure the city has an adequate supply of water. Specifically, the development and 

implementation of innovative water provision and conservation programs is 

encouraged, particularly through non-traditional methods, such as storm drainage 

system design integrating Low-Impact Development features to reduce 

hydromodification from development and other improvements to recharge 

groundwater.

City of San Luis Obispo General Plan

The City of San Luis Obispo General Plan includes goals, policies, and programs 

related to water supply and demand, with a focus on ensuring a long-term, reliable 

water supply to meet both current and future water demand associated with 

development envisioned by the General Plan.

3.12.2 METHODS OF EVALUATION

The components of the Build Alternative would have varying potential to result in 

environmental effects related to hydrology and water resources. The study area for 

hydrology and water resources is defined as the existing railroad right-of-way, the 

potential locations of the physical improvements, as well as conservative buffer 

areas around the proposed physical improvements. Below, this section discusses 

how each component was evaluated and what study area was considered.
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Impact Evaluation by Resource

Surface Waters

To determine potential impacts to hydrologic features, including streams, rivers, 

canals, etc. by the proposed physical improvements, national hydrography data 

from the United States Geologic Survey (USGS) was used. 

Permanent and temporary impacts were located by identifying where proposed 

physical improvements would intersect known flowlines. From this, the size of the 

impact was computed in linear feet in the jurisdictional areas. 

Groundwater

Impacts to groundwater resources were evaluated qualitatively by examining the 

potential for the proposed physical improvements to interfere with groundwater 

recharge or to deplete groundwater supplies. Groundwater resources serving 

communities along the alignment were identified, along with any potential impacts 

the physical improvements may have. For this analysis, it is assumed that among all 

proposed physical improvements, only proposed new station areas would have any 

significant potential to impact groundwater resources due to the likely addition of

impervious surface area. Other proposed improvements, such as new tracks, would 

not introduce substantial new impervious areas.

Floodplain

To determine the extent to which proposed physical improvements could be located 

within areas of subject to heightened flood risk (i.e. 100-year floodplains or other 

SFHAs), Federal Emergency Management Agency (FEMA) flood maps were 

consulted. The analysis computes acreages of proposed improvements within such 

areas.

Impaired Bodies

Impacts to impaired bodies of water within the exiting alignment and resulting from 

the proposed physical improvements were identified by using the US EPA 303(d) list. 

Any impacted surface waters were cross-checked with the 303(d) to determine if 

they are currently considered impaired. The linear feet of impaired water body 

were calculated for each of the Build Alternative physical improvements.
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Erosion

Potential erosion impacts were evaluated by using GIS data and aerial mapping to

identify proposed improvements that could occur in areas with steep slopes. Areas 

near steep slopes are more likely to experience erosion, particularly if proposed 

improvements would require substantial grading in such areas. 

3.12.3 AFFECTED ENVIRONMENT

Hydrological Resources in the Study Area

Surface Waters

Surface waters, including streams, lakes, rivers, ponds, and reservoirs, provide 

critical habitat for fish and wildlife, offer locations for groundwater recharge as well 

as direct pathways connecting resources. They also help convey flood waters, 

facilitating and maintaining water supply. (See Section 3.13, Biological Resources 

and Wetlands, for a discussion of wetlands and native species habitats). 

The major surface water resource within and immediately adjacent to the study 

area is the Salinas River. The Salinas River stretches approximately 184 miles

north/northwest, from the Santa Lucia and La Panza Mountain Ranges in San Luis 

Obispo County, through the Salinas Valley, and finally terminating in Monterey Bay 

near Castroville. The river meanders amidst 230,000 acres through the Salinas 

Valley floor, fed by several tributaries along the way. The river flow averages 

approximately 282,000 acre feet per year (AFY). Surface waters in the study area 

are shown in Figure 3.12-1.

Between Salinas and San Luis Obispo, the existing railroad crosses or is in close 

proximity to a number of other named streams, including the San Antonio River, 

Nacimiento River, Jack Creek, Santa Margarita Creek, Paso Robles Creek, Atascadero 

Creek, Chualar Creek, Stonewall Creek, Chalone Creek, Pancho Rico Creek, Sargent 

Creek, San Lorenzo Creek, Pine Creek, San Marcos Creek, Yerba Buena Creek, 

Paloma Creek, Graves Creek, Brizzolara Creek, Stenner Creek, and several unnamed 

creeks. 

Groundwater

Rainfall, snowmelt, and other types of water infiltration may penetrate the ground 

surface moving downward through spaces between soil particles, eventually 

encountering an impermeable layer. At this impermeable layer water begins to 

build up, ultimately becoming an aquifer. A groundwater basin contains one large 

aquifer or several connected and interrelated aquifers. Groundwater basins are 
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Draft Program EIS/EIR 3.12 Hydrology and Water Resources

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distinguished by natural or artificial divides, such as impermeable layers, in the 

water table. Precipitation as well as artificial infiltration can serve to recharge the 

groundwater basin. Groundwater recharge is most effective in areas where surface 

water is easily able to penetrate into the ground, such as along undeveloped river 

channels or beneath lakes.

Groundwater is an important resource to Monterey County. Overall, the 

groundwater is considered to be of good quality; however, localized groundwater 

quality issues exist, resulting from seawater intrusion in northern Monterey County 

(not an issue for the inland Salinas Valley) and nitrate contamination. Through 

Monterey County and parts of San Luis Obispo County, the Coast Corridor study 

area lies within the Salinas River Basin, extending a length of approximately 130 

miles. The Salinas River Basin consists of one large hydrologic unit consisting of four 

subareas, each containing their own hydrogeological and recharge characteristics. 

Water can move freely between them as they are not separated by any horizontal 

flow barrier. Groundwater resources in the study area are shown in Figure 3.12-2.

Groundwater is the primary water resource in the Salinas Valley and supplies a 

variety of uses, including irrigation, as well as domestic, municipal, and industrial 

purposes. In the Salinas Valley, groundwater recharge occurs primarily through the 

Salinas River, Arroyo Seco River, and some infiltration from rainfall. Lake San 

Antonio serves in part to collect water to recharge the San Antonio River, a tributary 

to the Salinas River. Some infiltration from small streams and inflow from bedrock 

areas adjoining the basin does occur, but to a much lesser extent.1

San Luis Obispo County obtains approximately 80 percent of its water supply from 

groundwater.2 As of 2014, Paso Robles relies entirely on groundwater, drawn from 

a large aquifer known as the Paso Robles Basin and the Salinas River Underflow. 

However, in 2015, Paso Robles is scheduled to begin receiving surface water (4,000 

AFY) from the Lake Nacimiento Water Project.3

The City of San Luis Obispo obtains water from Santa Margarita Lake, Whale Rock 

Reservoir, Nacimiento Reservoir, recycled water from the city’s Water Reclamation 

Facility (WRF), and groundwater. The city’s groundwater basin is relatively small 

and recharges quickly after rainfall events. Currently, the city operates one potable 

and one non-potable well. Two of the city’s largest producing wells were shut down 

after elevated nitrate levels were detected. The potable well produces 

 

1

County of Monterey, 2006, pp. 4.3-2-4.3-6

2

County of San Luis Obispo,, 2009, p. 3.7-1

3

City of Paso Robles, 2014
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approximately 11 AFM, about 2 percent of the city’s total water use. The nonpotable well serves construction activities in the area, such as soil compaction and 

dust control. Two additional wells are operated by the Laguna Lake Golf Course that 

serve to help meet irrigation demands at the course. The remainder of the 

irrigation demand for the golf course is met by the WRF.4

Floodplains

Floodplains are flatlands adjacent to rivers, lakes, and oceans that are subject to 

flooding when the nearby water body overflows, resulting in a variety of 

geomorphic and hydrological processes. A total of 49 acres of SFHAs have been 

designated within the Coast Corridor study area, and are shown in Figure 3.12-3. 

Water Quality Issues

Impaired Bodies

Impaired water bodies are those that do not meet water quality standards after 

application of effluent limits under the Clean Water Act (CWA). Water bodies with 

impaired water quality in the vicinity of the Coast Corridor study area include 

Atascadero Creek, Chualar Creek, Salinas River, San Lorenzo Creek, and Stenner 

Creek.5 These water bodies are considered impaired because they exceed the limits 

for fecal coliform, e. coli, low dissolved oxygen, boron, chloride, electrical 

conductivity, sodium, pH, chlordane, pesticides, total dissolved solids, toxaphene, 

nitrate, polychlorinated biphenyls (PCBs), enterococcus, diazinon, chlorpyrifos, 

dichlorodiphenyldichloroethane (DDD), and a number of other pollutants.

Erosion Potential

Erosion is the slow deterioration of land surface by flowing water, wind, waves, and 

corrosion, typically leading to soil loss and degraded water quality. Soil erosion can

occur in areas near steep slopes, and during construction activities that involve 

grading and other earth moving activities. See Section 3.11 Geology, Soils, and 

Minerals for an in-depth discussion of soil erosion in Monterey and San Luis Obispo 

Counties.

 

4

City of San Luis Obispo, , 2010, pp. 8.1-8.4

5

California EPA, 2013
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Most of the Coast Corridor study area has low soil erosion potential; very few areas 

are identified as having moderate to severe erosion potential. The topography of 

the existing Coast Corridor study area is predominately flat; however, several 

portions of the alignment run adjacent to areas with steeper topography, where any 

ground disturbance would increase the potential for erosion and sedimentation.

3.12.4 ENVIRONMENTAL CONSEQUENCES

No Build Alternative

The No Build Alternative represents the continuation of existing rail operations and 

physical components, and assumes the perpetuation of existing freight and 

passenger service between Salinas and San Luis Obispo. The only physical 

improvement expected under the No Build Alternative would be the installation of 

positive train control (PTC), which would provide increased safety for freight and 

passenger trains. PTC equipment would likely be installed within the existing 

railroad right-of-way or would modify existing signaling equipment, and train 

operations would continue as it currently does. As a result, impacts to hydrology 

and water resources would not change under current operation, and no new 

impacts would occur.

Build Alternative

Surface Waters/Impaired Water Bodies

The Build Alternative could result in potential proximity impacts to surface waters 

through runoff during construction activities, operation-related pollution in areas 

immediately adjacent to surface waters, and potential surface water crossings. 

Table 3.12-1 below shows potential impacts to surface waters resulting from the 

various elements of the Build Alternative. Potential temporary and permanent

surface water impacts are reported as linear feet, which represents areas in which 

Build Alternative components would come within close proximity to surface water 

resources. For example, construction activities occurring to upgrade existing 

alignment #1 would temporarily be in close proximity to 83 linear feet of surface 

waters. Once operational, these upgrades would be within the existing railroad 

right-of-way and would not be in close proximity to any water resources. As such, 

no permanent impacts are reported.
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Table 3.12-1 Potential Proximity Impacts to Surface Waters 

Build Alternative 

Components

Surface Water Impacts (linear feet)

Temporary Permanent

Salinas Powered Switch 0 0

Upgrades to Existing Alignment 

Section #1 

83 0

Spence Siding Extension 130 83

Upgrades to Existing Alignment 

Section #2 

2,411 0

Gonzales Powered Switch 0 0

Soledad Powered Switch 0 0

Soledad New Passenger Station 0 0

Harlem/Metz Curve Realignments 302 0

Chalone Creek New Siding 0 0

Upgrades to Existing Alignment 

Section #3

120 0

Coburn Curve Realignments 61 0

King City Siding Extension 133 100

King City New Passenger Station 0 0

King City Powered Switch 0 0

Upgrades to Existing Alignment 

Section #4

0 0

MP 165 Curve Realignment 403 100

San Lucas New Siding 0 0

Upgrades to Existing Alignment 

Section #5

1,732 0

MP 172 Track Realignment 785 150

San Ardo Powered Switch 0 0
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Build Alternative 

Components

Surface Water Impacts (linear feet)

Getty/Bradley Curve 

Realignments

1,636 417

Bradley Siding Extension 109 109

Bradley Powered Switch 0 0

Upgrades to Existing Alignment 

Section #6

1,076 0

Upgrades to Existing Alignment 

Section #7

287 0

McKay/ Wellsona Curve 

Realignments

0 0

McKay East Powered Switches 0 0

Wellsona New Siding 123 124

Upgrades to Existing Alignment 

Section #8

612 0

Wellsona/ Paso Robles Curve 

Realignments

0 0

Templeton Siding 267 227

Templeton/ Henry Curve 

Realignments

0 0

Upgrades to Existing Alignment 

Section #9

1,846 0

Henry/Santa Margarita Curve 

Realignment

5,719 305

Santa Margarita Powered Switch 0 0

Cuesta Second Main Track 5,986 749

Upgrades to Existing Alignment 

Section #10

3,620 0

Totalsa27,442a2,264a

Note: a) Rounded to the nearest whole number.

Source: ICF, 2013
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The Build Alternative would result in some potential proximity impacts to surface 

waters, including potential crossings of 17 streams and rivers on 117 occurrences.6

More specific construction-period and operational impact discussions are provided 

below. 

Construction-Period Effects

Construction activities could result in potential proximity impacts to approximately 

5.2 miles of surface waters in the study area. Construction activities may also result 

in potential proximity impacts to water quality along the corridor. During 

construction, erosion and runoff could result in an increased risk of sedimentation in 

nearby surface waters. This mainly results from the proximity of construction work 

and associated staging areas, vehicle ingress/egress, etc. to surface waters. The 

Henry/Santa Margarita Curve Realignment and the Cuesta Second Main Track would

both affect approximately 1 mile of surface waters each during construction 

activities. Construction of the King City Siding Extension could result in a potential 

temporary impact to the San Lorenzo Creek; however, this impact would extend for 

only 133 linear feet. Upgrades to Existing Alignment section #10 would potentially 

impact just over a half mile (3,620 linear feet) of surface waters during construction 

activities. Following construction work, these impacted areas would be restored 

back to their original condition.

Operational Effects

Five of the 17 streams and/or rivers that would be crossed by one or more of the 

elements of the Build Alternative are considered impaired. Of the impaired water 

bodies in the Corridor, San Lorenzo Creek is the only body of water that is not 

currently crossed by the existing alignment. The proposed King City Siding Extension

is the only proposed physical improvement that would add a new crossing of San 

Lorenzo Creek. 

Once operational, the number of daily trains on the corridor would increase, as such 

there would be increased potential for operation-related pollutants to enter the 

environment. Potential permanent proximity impacts could occur to approximately 

0.4 miles (2,264 linear feet) of surface waters. Like construction-period effects, 

these impacts would result from the proximity of the various proposed 

improvements (new sidings, siding extensions, etc.) and subsequently, close 

proximity of trains to surface waters. The King City Siding Extension has the 

potential to result in impacts to the San Lorenzo Creek for approximately .02 mile

 

6 More than 17 streams may be crossed; however, of all the streams crossed in the study area, only 17 

are named.
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(100 linear feet) once operational. Operation of the Cuesta Second Main Track 

could result in approximately 0.15 mile (749 linear feet) of potential impacts to 

surface waters. All of the remaining proposed new sidings/siding extensions would 

have potential impacts to already affected surface waters in a length of less than 

one tenth of a mile in the vicinity of the alignment.

Erosion Potential

Construction-Period Effects

Several elements of the Build Alternative could result in potential erosion impacts

during construction. Particularly the Harlem/Metz Curve Realignment, New Chalone 

Creek Siding, Coburn Curve Realignments, Bradley Siding, and Getty/Bradley Curve 

Realignments are located near steep slopes and could result in potential erosion 

impacts. The Cuesta Second Main Track is proposed in an area near steep 

topography; however, potential for soil erosion is low in this area as it is forested 

and agricultural uses are negligible. The Harlem/Metz and Coburn Curve 

Realignments would move the track further away from sloping hillside areas. These 

realignments, along with the Chalone Creek New Siding, would be located on

relatively flat land, thus reducing the potential for erosion and potentially creating a 

beneficial effect. 

Operational Effects

Once operational, the Build Alternative would have minimal potential to result in 

erosion as erosion is typically associated with grading, and other land disturbing 

activities that occur during construction.

Groundwater

Construction-Period Effects

Little groundwater use is anticipated for construction of all of the proposed physical 

improvements. Curve realignments, siding extensions, new power switches, and the 

second main track will have little to no impact to groundwater as construction 

activity associated with these improvements does not require water. Construction 

of the new stations, as well as concrete platforms would require water. Water use 

may also be needed during construction activities for dust control and other best 

management practices (BMPs); however, this use would be minimal and temporary. 

Furthermore, construction activities would truck water to the sites rather than need 

to draw it from wells, which would have no impact to groundwater resources

located within the study area. Since permanent sources of water are not needed for 

construction, new wells would not be developed; thus study area groundwater 

would not be depleted.
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Operational Effects

Both Soledad and King City get municipal water from groundwater. The new station 

areas proposed in Soledad and King City will require some new water use to operate 

restroom facilities and offer drinking water. Water use at existing stations (Salinas, 

San Luis Obispo, and Paso Robles) may increase as ridership is projected to increase

(add 124,000 annual riders by 2020)7 with the improved Coast Corridor service. 

Salinas draws at least a portion of its water from groundwater resources and Paso 

Robles relies completely on groundwater for its municipal water as of 2014. 

However, water use is minimal as the existing stations do not offer shower facilities

and only supply water for restroom and drinking water amenities. Therefore, 

although increased operational demand for groundwater may occur with the 

proposed physical improvements, no significant increase in use is anticipated. 

Floodplain

In the study area, 100-year flood hazard areas (or SFHAs) exist around flat lands 

surrounding the Salinas River and creeks in San Luis Obispo County. Portions of the 

existing alignment are within the 100-year floodplain. Portions of the railway within 

the floodplain are at risk of being inundated and potentially impassible during a 

storm event. Table 3.12-2 below lists the elements of the Build Alternative that

would be located within the designated 100-year floodplain.

Table 3.12-2 Acreage of Proposed Improvements within 100-Year Floodplain 

Build Alternative Components 100yr Floodplain (Acres)

Temporary Permanent

Salinas Powered Switch 0 0

Upgrades to Existing Alignment Section 

#1 

0 0

Spence Siding Extension 0 0

Upgrades to Existing Alignment Section 

#2 

5 0

Gonzales Powered Switch 0 0

Soledad Powered Switch 0 0

Soledad New Passenger Station 0 0

 

7

Caltrans Division of Rail, 2013b
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Build Alternative Components 100yr Floodplain (Acres)

Harlem/Metz Curve Realignments 61 14

Chalone Creek New Siding 0.5 .03

Upgrades to Existing Alignment Section 

#3

1 0

Coburn Curve Realignments 20 1.5

King City Siding Extension 1 1

King City New Passenger Station 0 0

King City Powered Switch 0 0

Upgrades to Existing Alignment Section 

#4

8 0

MP 165 Curve Realignment 6 1

San Lucas New Siding 0 0

Upgrades to Existing Alignment Section 

#5

6 0

MP 172 Track Realignment 6 .01

San Ardo Powered Switch 0 0

Getty/Bradley Curve Realignments 19 3

Bradley Siding Extension 0 0

Bradley Powered Switch 0 0

Upgrades to Existing Alignment Section 

#6

2 0

Upgrades to Existing Alignment Section 

#7

2 0

McKay/ Wellsona Curve Realignments 10 0.2

McKay East Powered Switches 0 0

Wellsona New Siding 1 0.2

Upgrades to Existing Alignment Section 

#8

13 0
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Build Alternative Components 100yr Floodplain (Acres)

Wellsona/ Paso Robles Curve 

Realignments

0.9 0

Templeton Siding 6 3

Templeton/ Henry Curve Realignments 0 0

Upgrades to Existing Alignment Section 

#9

10 0

Henry/Santa Margarita Curve 

Realignment

19 4

Santa Margarita Powered Switch 0 0

Cuesta Second Main Track 0 0

Upgrades to Existing Alignment Section 

#10

2 0

Totalsa200 29

Note: a Rounded to the nearest whole number.

Source: ICF, 2013

Elements of the Build Alternative would be located within approximately 229 acres 

of the 100-year flood zone, putting them at risk of inundation by flooding.

Temporary inundation can result in travel delays. Over time, frequent temporary 

inundations could result in damage to tracks or other rail facilities. 

Construction-Period Effects

200 of the acres potentially affected would be within SFHAs only during 

construction activities. Temporary staging areas associated with construction of the 

Coburn, Getty/Bradley, Harlem/Metz, and Henry/Santa Margarita Curve 

Realignments would result in the majority of temporary acreage identified as 

potentially within SFHAs. These areas would only be at risk of flood impacts during 

the construction period, and measures could be taken to reduce the likelihood of 

such impacts (storing equipment on high ground, etc.). 

Operational Effects

The remaining 29 acres identified within the flood zone would be required for 

implementation of specific physical improvements. Almost half of this amount (14 

acres) is associated with the potential construction of the several segments of the 

Harlem-Metz curve realignment, near a stretch of the Salinas River. Given the 

relatively small amount of land that would be permanently affected within the 
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Draft Program EIS/EIR 3.12 Hydrology and Water Resources

3.12-17

existing 100-year flood zone and that impacts to the flood zone would be spread 

across a relatively wide geography within the study area, the Build Alternative 

would not result in substantial increase in flood elevations nor substantially shift the 

location of flood zones. These areas would however be at risk of flood inundation 

during a severe weather event.

3.12.5 AVOIDANCE, MINIMIZATION, AND MITIGATION 

STRATEGIES

The Build Alternative will be designed to minimize impacts to biological resources

along the Corridor. The following strategies have been identified at this preliminary 

stage to avoid, minimize, and/or mitigate any potentially significant impacts. 

Surface Waters

Strategies to reduce potential impacts on surface waters include the following:

A-BIO-1. Many of the potential impacts to water resources could be avoided 

through project-level design. For example, siding extension impact areas were 

analyzed assuming one mile extension areas could occur entirely on one side or the 

other. In the event that one end of a siding extension will impact a surface water 

body, the siding extension could be designed on the opposite side and away from 

the water resource area, thus removing the impact altogether.

MIN-BIO-2. National Pollutant Discharge Elimination System (NPDES) permits and 

Storm Water Pollution Prevention Plans (SWPPP) should be obtained prior to 

implementing elements of the Build Alternative. California NPDES permit 

requirements would be followed and BMPs would be implemented as mandated. 

These may include measures to provide permeable surfaces where feasible and to 

retain and treat stormwater onsite using catch basins and treatment wetlands. 

These measures will be particularly valuable in areas where new stations would be 

constructed and/or paved parking areas would be developed or expanded. The 

SWPPP would include BMPs to minimize potential sediment transport due to 

construction activities, including obligatory erosion control techniques, stormwater 

management, and channel dewatering for all stream/river crossings. The SWPPP 

should also include measures to control the overall amount and quality of 

stormwater runoff to regional systems. Potential BMPs may include the following:

 Practices that minimize contact between construction materials, equipment, 

and maintenance supplies with stormwater;
Coast Corridor

3.12 Hydrology and Water Resources Draft Program EIS/EIR

3.12-18

 Practices that reduce soil erosion including watering for dust control, perimeter 

silt fences, placement of rice straw bales, sediment basins, and soil stabilization; 

and

 Practices that maintain water quality including filtration, detention, and 

retention systems, constructed wetland systems, biofiltration/bioretention 

systems, grass buffer strips, ponding areas, organic mulch layers, planting soil 

beds, sand beds, or vegetated systems (biofilters) such as vegetated swales and 

grass strips designed to convey and treat either shallow flow (swales) or 

sheerflow (filter strips) runoff.

MM-BIO-3. Obtain permits as required under Sections 401 and 404 of the CWA and 

comply with mitigation measures required in the permits. Mitigation measures may 

include compensation for habitat loss involving habitat restoration, reconstruction 

onsite, or habitat replacement offsite, with the ultimate goal of ensuring minimal 

impact to surface water quality.

MIN-BIO-4. For any water body designated as Navigable, permit conditions required 

under Section 10 of the Rivers and Harbors Act would be adhered to.

MIN-BIO-5. A Lake or Streambed Alteration Agreement would need to be obtained 

for any work that would take place along the banks of surface water bodies.

MIN-BIO-6. To manage potential fuel or other spills a spill prevention and 

emergency response plan would be developed and implemented.

Floodplains

Strategies to reduce potential impacts on floodplains should include the following:

A-BIO-7. Prior to implementing physical improvements that would introduce new 

structures in the study area, such as curve realignments, further evaluation of

potential 100 year flood risk areas should be conducted. Construction of facilities 

within floodplains should be avoided where feasible, and floodplains temporarily 

impacted by construction activities should be restored as much as possible so they 

can function as before. 

MIN-BIO-8. Where avoidance is infeasible, the footprint of facilities within the 

floodplain should be minimized to the extent possible. All opportunities for 

redesign or modification to minimize flooding risk and potential harm to or within 

the floodplain should be assessed. For instance, siding extensions can be designed 

to either extend from the north or south end of the existing siding, thus potentially 

avoiding a flood-prone area.
Coast Corridor

Draft Program EIS/EIR 3.12 Hydrology and Water Resources

3.12-19

Groundwater

Strategies to reduce potential impacts from construction and operation of the 

physical improvements on groundwater resources should include the following:

A-BIO-9. Design facilities that are elevated and/or permeable so as to not affect 

recharge potential where construction is required in areas of potentially substantial 

groundwater discharge or recharge.

MIN-BIO-10. Minimize development of facilities in areas that have substantial 

groundwater discharge or that would affect recharge.

MM-BIO-11. Obtain waste discharge permits where required.

MIN-BIO-12. Obtain a NPDES permit and implement permit requirements as well as 

BMPs that would control the release of contaminants near areas of surface water or 

groundwater recharge.

MIN-BIO-13. Consider use and retention of native materials with high infiltration 

potential at the ground surface in areas that are critical to infiltration for 

groundwater recharge.

3.12.6 SUBSEQUENT ANALYSIS

Additional analysis to further identify potential impacts on hydrology and water 

resources should be needed. The subsequent analysis should include the following;

 Further assessment of potential construction and facility impacts on surface 

waters and hydrology.

 As specific locations and facility designs are developed, further analysis of 

potential impacts on floodplains.

 Field surveys of potential water impacts to further analyze potential impacts on 

water quality, obtain required permits from the appropriate agencies, and 

develop suitable BMPs.

 Assessment of significant alteration in water-flow and drainage patterns, 

including increased stormwater runoff, or changes to groundwater discharge or 

recharge.

 Analysis of potential impacts of the physical improvements on groundwater 

recharge and infiltration systems.

 Identification of shallow groundwater areas to determine potential impacts 

from dewatering during construction.
Coast Corridor

3.12 Hydrology and Water Resources Draft Program EIS/EIR

3.12-20

 Assessment of how the various physical improvements would contribute to 

additional impervious surface and the subsequent potential additional impacts 

to surface runoff. This assessment would include potential mitigation measures.

 Field surveys of groundwater discharge/recharge conditions including additional 

analysis of groundwater conditions with information from other geotechnical 

studies.
Spence Siding

H

EA-2

EA-1 H

H

EA-1

Chualar

Spreckels

£¤101

Salinas

Limekiln Creek

Rana Creek

Alisal Creek

El Toro Creek

Gabilan Creek

Natividad Creek

Salinas River

Chualar Creek

Main Canal

Quail Creek

Coast Corridor Improvements EIR/EIS

a

b

c

d

e

f

g

h

Surface Waters in the Project Area

Figure 3.12-1a

±

0 1 2

Miles

Legend

Streams/Rivers

Potentially Affected Waters

Project Components

Existing Alignment

Sidings

Realignments

Source: ICF International, 2013

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Harlem/Metz

Harlem/Metz

Harlem/Metz New Chalone Creek

H

EA-3

EA-2 H

Gonzales

Soledad

£¤101

£¤101

Stonewall Creek

Arroyo Seco

Chalone Creek

McCoy Creek

Johnson Creek

Salinas River

Coast Corridor Improvements EIR/EIS

a

b

c

d

e

f

g

h

Surface Waters in the Project Area

Figure 3.12-1b

±

0 1 2

Miles

Legend

Streams/Rivers

Potentially Affected Waters

Project Components

Existing Alignment

Sidings

Realignments

Source: ICF International, 2013

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1:75,000
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Harlem/Metz Realign Tracks at MP 165

Coburn

Coburn 

Harlem/Metz

King City Siding

New Chalone Creek

E

H

EA-4

EA-3 H

H

EA-3

EA-2 H

Greenfield

King

City

£¤101

Chalone Creek

Monroe Creek

Arroyo Seco

San Lorenzo Creek

Reliz Creek

Salinas River

Topo Creek

Coast Corridor Improvements EIR/EIS

a

b

c

d

e

f

g

h

Surface Waters in the Project Area

Figure 3.12-1c

±

0 1 2

Miles

Legend

Streams/Rivers

Potentially Affected Waters

Project Components

Existing Alignment

Sidings

Realignments

Source: ICF International, 2013

Page 1c ±

1:75,000
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Realign Tracks at MP 165 Realign Tracks at MP 172

San Lucas Siding

EA-5

H

EA-4

H

H

EA-4

UV198

San

Lucas

£¤101

£¤101

Pine Creek

Salinas River

Coast Corridor Improvements EIR/EIS

a

b

c

d

e

f

g

h

Surface Waters in the Project Area

Figure 3.12-1d

±

0 1 2

Miles

Legend

Streams/Rivers

Potentially Affected Waters

Project Components

Existing Alignment

Sidings

Realignments

Source: ICF International, 2013

Page 1d ±

1:75,000
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Getty/Bradley

Getty/Bradley

Getty/Bradley

Bradley Siding

EA-6 H

H

EA-6

H

EA-5

Bradley

San Ardo

£¤101

£¤101

San Antonio River

Hames Creek

Pancho Rico Creek

Big Sandy Creek

San Antonio River

Hames Creek

Salinas River

Sargent Creek

Coast Corridor Improvements EIR/EIS

a

b

c

d

e

f

g

h

Surface Waters in the Project Area

Figure 3.12-1e

±

0 1 2

Miles

Legend

Streams/Rivers

Potentially Affected Waters

Project Components

Existing Alignment

Sidings

Realignments

Source: ICF International, 2013

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Wellsona/Paso Robles

McKay/Wellsona

McKay/Wellsona

McKay/Wellsona

Wellsona Siding

H

EA-8

H

H

EA-7

EA-6 H

EA-7

San

Luis

Obispo County

Monterey County

El Paso de

Robles (Paso

Robles)

San

Miguel

£¤101

£¤101

San Antonio River

San Jacinto Creek

Huerhuero

Creek

Big

Sandy Creek

Estrella River

San Marcos Creek

Nacimiento River

Mustard Creek

Salinas River

Coast Corridor Improvements EIR/EIS

a

b

c

d

e

f

g

h

Surface Waters in the Project Area

Figure 3.12-1f

±

0 1 2

Miles

Legend

Streams/Rivers

Potentially Affected Waters

Project Components

Existing Alignment

Sidings

Realignments

Source: ICF International, 2013

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Henry/Santa Margarita Templeton/Henry

Henry/Santa Margarita

Henry/Santa Margarita

Henry/Santa Margarita

Templeton Siding

Second Main Line

H

EA-10

EA-9 H

H

EA-9

EA-8 H

UV46

Atascadero

El Paso de

Robles (Paso

Robles)

Templeton

£¤101

£¤101

Eagle Creek

Morro Creek

Hale Creek

Trout Creek

Willow Creek

Salinas River

Toro Creek

Tassajera Creek

South Fork Santa Rita Creek

West Branch

Huerhuero

Creek

Paso

Robles Creek

East Fork Morro Creek

Graves Creek

Jack Creek

Atascadero Creek

Paloma Creek

Sheepcamp Creek

Santa Rita Creek

Coast Corridor Improvements EIR/EIS

a

b

c

d

e

f

g

h

Surface Waters in the Project Area

Figure 3.12-1g

±

0 1 2

Miles

Legend

Streams/Rivers

Potentially Affected Waters

Project Components

Existing Alignment

Sidings

Realignments

Source: ICF International, 2013

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H

enry/SantaMargarita

SecondMainLine

E

A

-

1

0

H

H

E

A

-

1

0

E

A

-

9

H

UV1

UV227

Arroyo

Grande

SanLuis

Obispo

£¤101

£¤101

Wittenberg

Creek

Yerba

B

u

e

naC

re

e

k

Ri

nconada

Creek

Chorro Creek

Trout

Creek

Davenport Creek

San

Luis

Obispo

Creek

Vasquez Creek

Potrero Creek

Tassajera Creek

Pismo Creek

East Corral de Piedra Creek

V

ill

a

Cre

ek

Little

Falls

Creek

Stenner Creek

Dairy Creek

West Corral de Piedra Creek

Brizzolara Creek

Burrito Creek

CoastCorridorImprovementsEIR/EIS

a

b

c

d

e

fg

h

SurfaceWatersintheProjectArea

Figure

3.12-1h

±

012

Miles

Legend

Streams/Rivers

PotentiallyAffectedWaters

ProjectComponents

ExistingAlignment

Sidings

Realignments

Source:ICFInternational,2013

Page1h

±

1:75,000
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King City Siding

Templeton Siding

Second Main Line

New Chalone Creek

Wellsona Siding

San Lucas Siding

Bradley Siding

Spence Siding

McKay/Wellsona

Henry/Santa Margarita

McKay/Wellsona

Coburn

Harlem/Metz

Realign Tracks at MP 172

Coburn

Realign Tracks at MP 165

Harlem/Metz

Getty/Bradley

Templeton/Henry

Getty/Bradley

Wellsona/Paso Robles

Atascadero Henry/Santa Margarita

Bradley

El Paso de Robles

(Paso Robles)

King City

Salinas

San Ardo

San Lucas

San Luis Obispo

San Miguel

Soledad

Templeton

UV46

UV145

UV198

UV25

UV1

£¤101

§ ̈¦5

Coast Corridor Improvements EIR/EIS

Groundwater Resources in Project Area

Figure 3.12-2 Source: ICF International, 2013

Existing Alignment

Realignments

Sidings

Aquifers

San Luis Obispo Valley

180/400 Foot

East Side

Forebay

Paso Robles Area

Upper Valley

± 0 6 12

Miles
Coast Corridor

3.12 Hydrology and Water Resources Draft Program EIS/EIR

3.12-24

Page Intentionally Left Blank
Spence Siding

H

EA-2

EA-1 H

H

EA-1

Chualar

Spreckels

Salinas

Coast Corridor Improvements EIR/EIS

a

b

c

d

e

f

g

h

Special Flood Hazard Areas

Figure 3.12-3a

±

0 1 2

Miles

Legend

Special Flood Hazard Areas

Potentially Affected Flood Hazard Areas

Project Components

Existing Alignment

Sidings

Realignments

Source: ICF International, 2013

Page 3a ±

1:75,000
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Harlem/Metz Harlem/Metz

Harlem/Metz New Chalone Creek

H

EA-3

EA-2 H

Gonzales

Soledad

Coast Corridor Improvements EIR/EIS

a

b

c

d

e

f

g

h

Special Flood Hazard Areas

Figure 3.12-3b

±

0 1 2

Miles

Legend

Special Flood Hazard Areas

Potentially Affected Flood Hazard Areas

Project Components

Existing Alignment

Sidings

Realignments

Source: ICF International, 2013

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1:75,000
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Harlem/Metz Realign Tracks at MP 165

Coburn

Coburn 

Harlem/Metz

King City Siding

New Chalone Creek

E

H

EA-4

EA-3 H

H

EA-3

EA-2 H

Greenfield

King

City

£¤101

£¤101

Coast Corridor Improvements EIR/EIS

a

b

c

d

e

f

g

h

Special Flood Hazard Areas

Figure 3.12-3c

±

0 1 2

Miles

Legend

Special Flood Hazard Areas

Potentially Affected Flood Hazard Areas

Project Components

Existing Alignment

Sidings

Realignments

Source: ICF International, 2013

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1:75,000
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Realign Tracks at MP 165 Realign Tracks at MP 172

San Lucas Siding

EA-5

H

EA-4

H

H

EA-4

UV198

San

Lucas

£¤101

£¤101

Coast Corridor Improvements EIR/EIS

a

b

c

d

e

f

g

h

Special Flood Hazard Areas

Figure 3.12-3d

±

0 1 2

Miles

Legend

Special Flood Hazard Areas

Potentially Affected Flood Hazard Areas

Project Components

Existing Alignment

Sidings

Realignments

Source: ICF International, 2013

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1:75,000
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Getty/Bradley

Getty/Bradley

Getty/Bradley

Bradley Siding

EA-6 H

H

EA-6

H

EA-5

Bradley

San Ardo

£¤101 £¤101

Coast Corridor Improvements EIR/EIS

a

b

c

d

e

f

g

h

Special Flood Hazard Areas

Figure 3.12-3e

±

0 1 2

Miles

Legend

Special Flood Hazard Areas

Potentially Affected Flood Hazard Areas

Project Components

Existing Alignment

Sidings

Realignments

Source: ICF International, 2013

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Wellsona/Paso Robles

McKay/Wellsona

McKay/Wellsona

McKay/Wellsona

Wellsona Siding

H

EA-8

H

H

EA-7

EA-6 H

EA-7

San

Luis

Obispo County

Monterey County

El Paso de

Robles (Paso

Robles)

San

Miguel

£¤101

£¤101 £¤101

Coast Corridor Improvements EIR/EIS

a

b

c

d

e

f

g

h

Special Flood Hazard Areas

Figure 3.12-3f

±

0 1 2

Miles

Legend

Special Flood Hazard Areas

Potentially Affected Flood Hazard Areas

Project Components

Existing Alignment

Sidings

Realignments

Source: ICF International, 2013

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Henry/Santa Margarita Templeton/Henry

Henry/Santa Margarita

Henry/Santa Margarita

Henry/Santa Margarita

Templeton Siding

Second Main Line

H

EA-10

EA-9 H

H

EA-9

EA-8 H

Atascadero

El Paso de

Robles (Paso

Robles)

Templeton

£¤101

Coast Corridor Improvements EIR/EIS

a

b

c

d

e

f

g

h

Special Flood Hazard Areas

Figure 3.12-3g

±

0 1 2

Miles

Legend

Special Flood Hazard Areas

Potentially Affected Flood Hazard Areas

Project Components

Existing Alignment

Sidings

Realignments

Source: ICF International, 2013

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Henry/Santa Margarita

Second Main Line

EA-10 H

H

EA-10

EA-9 H

Arroyo

Grande

San Luis

Obispo

£¤101

Coast Corridor Improvements EIR/EIS

a

b

c

d

e

f

g

h

Special Flood Hazard Areas

Figure 3.12-3h

±

0 1 2

Miles

Legend

Special Flood Hazard Areas

Potentially Affected Flood Hazard Areas

Project Components

Existing Alignment

Sidings

Realignments

Source: ICF International, 2013

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