Collect, compile, and evaluate existing studies and data; Review the projected irrigation water demand estimates;

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1 V. Capacity Impacts

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3 A. GROUNDWATER RESOURCES 1. Environmental Issue This section was prepared by Fugro-West and Firma, with assistance from Balance Hydrologics. The EIR groundwater investigations related to the potential for pumping Pismo Creek Alluvium wells were prepared by the landowner s consultants Cleath-Harris Geologists. Fugro-West and Balance Hydrologic provided CEQA peer review of the Cleath-Harris (CHG) analyses for the EIR. The complete Groundwater Supply Assessment prepared by Fugro West for the Planning Area Constraint Study (2009), the Cleath Harris Geologist study, Stream Characterization and Impact Studies and Well Testing Program for the Pismo Creek Alluvial Aquifers, October 2009, and the Balance Hydrologic and Fugro-West peer review memos of the CHG study are contained in the EIR Study Technical Appendix available on CD ROM. The Fugro West Constraint Study report, which forms the primary basis for the Environmental Setting portion of this EIR section, provides the technical basis for evaluating issues related to groundwater supply. The objective of the initial Constraint Study analysis was to identify the availability and reliability of the several potential sources of water supply that may be available to the project, including groundwater (from multiple aquifers), reclaimed produced water from the Price Canyon oil field operated by Plains Exploration and Production (PXP), reclaimed water from the wastewater treatment facility operated by the City of Pismo Beach, and the State Water Project (SWP). With the formulation of the Draft Price Canyon Specific Plan, groundwater resources are proposed to be used for only agricultural irrigation. This EIR section reproduces the Constraint Study groundwater analysis to thoroughly describe the environmental setting for groundwater resources. This section discusses three groundwater aquifers present in the Planning Area and focuses on the following objectives: Collect, compile, and evaluate existing studies and data; Review the projected irrigation water demand estimates; Assess the source aquifers of the existing project wells, the well yields, and the available yield of the producing aquifers to estimate the project groundwater supply capability; Evaluate the long-term capability of the groundwater supply sources to sustain the anticipated water demand from the aquifer(s); Compare the calculated water balance for the project based on projections of total demand balanced against the long-term reliability of the groundwater water supply sources, Review of the proposed PCSP groundwater pumping program and well testing for the Pismo Creek Alluvium; and, Price Canyon General Plan Update, SOI Change, Annexation and Specific Plan Program EIR V-A Groundwater Resources Page V-A1

4 Identification of potential impacts to groundwater and development of appropriate mitigation strategies to minimize impacts to groundwater and the Pismo Creek stream flow volume needed for habitat. Due to the interrelationship of groundwater hydrology to the water level in the Pismo Creek alluvial aquifer and, hence, the aquatic habitat in Pismo Creek, and the specific geologic and hydrologic analyses undertaken to evaluate this topic, the environmental analysis for the pumping effects on stream flow is presented in this section rather than section IV.C Biological Resources. The study area contains several groundwater wells as shown on Map V-A.1 Planning Area Groundwater Wells. The Spanish Springs Ranch holdings (North Ranch and South Ranch) include 14 wells (both shallow alluvial wells and deep formation wells); the Godfrey Ranch apparently includes four wells (all deep formation wells); and the Big Bird property includes several shallow alluvial wells. Available information on these wells varies from well to well and from ranch to ranch. The information provided to us for this analysis is described in subsequent report sections. Previous work conducted at the site or on projects nearby with relevance to the current study includes: Balance Hydrologics, Inc., 2008, Hydrology and Geology Assessment of the Pismo Creek Watershed. Central Coast Salmon Enhancement, 2008, Pismo Beach/Edna Valley Watershed Management Plan. Cleath and Associates, 2000, Ground Water Development on Avila Ranch, Price Canyon, San Luis Obispo County. Cleath and Associates, 2007, Hydrologic Map of Pismo Beach Watershed. Cleath and Associates, 2008a, Limits of Pismo Formation Aquifers in Indian Knob Valley. Cleath and Associates, 2008b, Status of Ground Water Studies in Price Canyon. Cleath and Associates, 2008c, Indian Knob Valley. Cleath and Associates, 2008d, Ground Water Availability from Price Canyon Alluvium. Fugro West Inc, 2005, Evaluation of Meadow Creek wells and Aquifer. Fugro West, Inc., 2007, Water Resources Assessment for the Los Robles Del Mar Supplemental Environmental Impact Report. King Ventures, 2007, Preliminary Project Description and Constraints Assessment for Price Canyon Master Plan, Pismo Beach. Padre Associates, Inc., 2008, Plains Exploration and Production Produced Water Treatment Facility, Subsequent Final Environmental Impact Report. As part of this study Fugro-West has reviewed each of the above documents and where appropriate has provided assessment on the conclusions within this document. Price Canyon General Plan Update, SOI Change, Annexation and Specific Plan Program EIR V-A Groundwater Resources Page V-A2

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6 INVESTIGATIVE METHODOLOGY To evaluate the geologic and hydrologic conditions of the various potential water supply sources from which the project is proposing to extract groundwater and to assess the relative impact on groundwater conditions should the project demand be extracted, the following work was conducted: reviewed geologic and hydrogeologic reports and maps, both published and unpublished were reviewed; reviewed and refined the geological interpretation of the aquifers and geology through the assessment and analysis of geologic cross-sections prepared by the applicant s consultant, prepared geologic and hydrogeologic maps and cross-sections, and reviewed available borehole logs; reviewed and re-analyzed aquifer testing data from previous reports where data was available; calculated hydraulic parameters for the aquifers where appropriate and where sufficient data existed; estimated recharge to the Pismo Formation aquifers by deep percolation through the use of local precipitation data, soil type, and slope analysis; calculated the outcrop areas of the aquifer materials in the Indian Knob valley; estimated recharge to the alluvial aquifer by streambed recharge by determining the area of contact between the alluvium and the bedrock from map interpretation, borehole logs and field reconnaissance. Seasonal alluvial sub flow was assessed from local stream flow and precipitation trends; groundwater quality data was collected, assessed and compared with trends observed in the region. calculated groundwater storage capacity of the Indian Knob Valley aquifer using the outcrop and cross section maps to determine available aquifer volume combined with groundwater level data to determine the saturated volume, and; estimated groundwater recharge to the aquifers, incorporating functions of recharge (e.g. precipitation recharge) and discharge (e.g. agricultural pumping). estimated the level and seasonal timing of pumping in the Pismo Creek Alluvium aquifer that would be required to maintain the minimum stream flow for aquatic habitat. Price Canyon General Plan Update, SOI Change, Annexation and Specific Plan Program EIR V-A Groundwater Resources Page V-A4

7 2. Environmental & Regulatory Setting General Plan Context and Planning Issues CITY OF PISMO BEACH GENERAL PLAN As discussed in more detail in section V-B Municipal Water Supply, the City obtains water from a variety of sources. As a matter of policy the General Plan requires any annexation proposal to demonstrate that long term sustainable water sources will be available to serve the annexed properties: F-40 - Annexation Areas All areas considered for annexation shall demonstrate sustained long-term water sources prior to approval for annexation. LU-R-3 - Future Urban Development on Parcels 2 and 3 (Big Bird and Loughead) A secure, reliable, long-term source of water to accommodate the intended urban development must be established. LU-R-4 - Golf Course & Recreational Development (Parcel 4 southern part of Spanish Ranch South) Landscape irrigation should use on-site water sources and reclaimed treated wastewater to the maximum extent practicable. SAN LUIS OBISPO COUNTY LOCAL AGENCY FORMATION COMMISSION (LAFCO) LAFCO has adopted the following policy requiring annexation proposals to demonstrate and adequate long-term source of water: In any proposal requiring water service, the Commission requires that the agency to which the annexation is proposed should demonstrate the availability of an adequate, reliable and sustainable supply of water. In cases where a phased development is proposed, the agency should demonstrate that adequate service capacity will be provided as needed for each phase. In cases where a proposed annexation will be served by an onsite water source, the proponent should demonstrate its adequacy. Regulatory Permits The beneficial reuse of reclaimed water by recharge and recovery is regulated by the Regional Water Quality Control Board and the State Department of Public Health. (Additional discussion is in EIR section IV-C Drainage, Flooding and Water Quality.) Environmental Setting The study area is located within the proposed Price Canyon Planning Area, generally along Price Canyon Road north of Pismo Beach and entirely within the Pismo Creek watershed. The study area is within the Pismo Hydrologic Subarea of the Santa Maria Groundwater Basin, as defined by the California Department of Water Resources (DWR, 2002). Price Canyon General Plan Update, SOI Change, Annexation and Specific Plan Program EIR V-A Groundwater Resources Page V-A5

8 For purposes of this study, the important geologic formations that underlie the area include the Recent-age alluvium, the Pismo Formation (particularly the Gragg and Edna members of the formation), and the Monterey Formation as shown on Map V-A.2 Geologic Map. The primary potential sources of groundwater supply in the study area include the Pismo Creek alluvium within Price Canyon, the Pismo Formation in the Indian Knob Valley area on the western flank of the watershed, and the Pismo Formation in the Oak Park area east of Pismo Creek. The generalized geology of the region is shown on Map V-A.2; geologic cross sections showing the spatial relationships of the geologic units are presented as Figures V-A.1 through A.5. PISMO CREEK ALLUVIUM Within the study area, Quaternary-age alluvium occurs within and immediately adjacent to the active channels of Pismo Creek and, to a lesser degree, Las Cuevitas Creek. The alluvium varies between 200 and 1,500 feet wide and is up to 70 feet in thickness. The alluvium consists of material eroded from upstream areas, composed of basal sand and gravel locally interbedded with clay layers. Pismo Creek and its tributary, Canada Verde, drain the Edna Groundwater Basin (Map V-A.2). However, the Pismo Creek alluvium is not continuous from the study area to the Edna Basin; bedrock highs within the creek bed create discontinuous alluvial sections from a point 4,000 to 5,000 feet north of the study area (near Ormonde Road) to the Edna Basin. Thus, the Edna Groundwater Basin aquifer and the Canada Verde alluvial section are not in direct hydraulic communication with the Pismo Creek alluvium within the Planning Area. Furthermore, the Edna Fault, which forms the southern boundary of the Edna Groundwater Basin, creates a subsurface barrier to flow in the water-producing aquifer underlying the alluvium (Map V-A.2 and Figure V-A.2). Within the Spanish Springs portion of the study area, the depth of the alluvium ranges from 31 and 70 feet deep, as determined by the drilling logs of six alluvial wells drilled in 1999 (Cleath and Associates, 2008d). As described above, north (upstream) of the study area, the thickness of the alluvium thins. Approximately 4,000 to 5,000 feet north of the study area, outcrops of shale and sandstone bedrock are present in the stream bed. This local bedrock outcrop constitutes a barrier, or a discontinuous hydraulic conduit, to groundwater flow as a water gap. The alluvial aquifer is recharged by underflow from upstream alluvium in hydraulic communication with the project site, surface flow (base flow and surface runoff) across the water gap, and by percolation of precipitation. The total volume of groundwater in storage in the alluvium in the study area is estimated to be approximately 500 to 600 acre-feet (af), calculated by estimating an alluvial areal extent of 140 acres, approximately 20 feet of saturated aquifer thickness, and an assumed specific yield of 0.2. This figure compares well with the 400 to 530 af of groundwater in storage estimated by Cleath and Associates (2008d). PISMO FORMATION IN THE INDIAN KNOB VALLEY The Indian Knob Valley aquifer is an informally named water-producing bedrock aquifer on the western edge of the Pismo Creek watershed (Map V-A.2). The main water-producing units of the aquifer are the Gragg and non-bituminous Edna sandstone members of the Pismo Formation. The aquifer is constrained by the Indian Knob fault to the north (Map V-A.2 and Price Canyon General Plan Update, SOI Change, Annexation and Specific Plan Program EIR V-A Groundwater Resources Page V-A6

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11 Figure V-A.1) and the non-water-producing members of the Pismo Formation, primarily the Miguelito member, to the south and southeast. Although the aquifer extends westward across the Pismo Creek watershed divide into Gragg Canyon and Squire Canyon, the effective edge for purposes of this analysis is the Pismo Creek watershed divide. The geologic structure of the Indian Knob Valley aquifer is dominated by a westward-plunging syncline with a northwest-southeast trend. The nature of the syncline is illustrated on Figure V-A.1, which shows the relationship of the water-producing zones with the non-waterproducing units, the underlying shales, and the Indian Knob fault. The approximate real extent of the non-bituminous Edna sandstone, which forms the base of the water-producing aquifer, is shown as the blue line delineation on Map V-A.2. The relationship of the western edge of the study area to the water-producing aquifer is shown on Figure V-A.3. As illustrated on the cross section, the water-producing Edna member dips to the west. The primary Spanish Springs North Ranch wells (wells 10, A, B, and the West Well) are all located in as optimal location as the property line limitations allow, however wells located farther west of the ranch wells could be expected to encounter greater thicknesses of saturated aquifer and would likely have greater yields, or at least a greater sustainable yield. The Pliocene-age beds of the Pismo Formation are composed primarily of sand interbedded with clay and silt layers. The Gragg and Edna sandstone members constitute the primary water-bearing members of the Pismo Formation within the study area; the Belleview and Miguelito members are typically poor water-producing units (Map V-A.2). The Gragg member is a massive to bedded, white to light-gray, medium-grained, well-sorted, poorly-indurated sandstone, locally composed of chert and pebble conglomerate. The groundwater-bearing portion of the Edna member is a buff to gray, fine- to medium-grained, non-bituminous, arkosic or quartz sandstone, and is generally soft and friable (Hall, 1973). Other Edna member sand horizons can be massive medium grained sandstones and bituminous sandstones, which generally are not high water-producing units. As described earlier, within the portion of the study area which overlies the Indian Knob Valley, only the Edna member of the Pismo Formation is present (Map V-A.2 and Figure V-A.3). The volume of groundwater in storage in the Edna member can be grossly calculated on the basis of the areal extent of the aquifers, the saturated thickness, and an assumed specific yield. The total groundwater in storage of the Edna sandstone is approximately 75,000 af (Cleath and Associates, 2008b), although only a small portion of that volume is available for extraction by wells. The largest source of recharge to the Edna member aquifer is likely from percolation of precipitation, thus the areal extent of the outcrop or subcrop of the aquifer is important. From Map V-A.2, it is estimated that approximately 880 acres of the Edna member of the Pismo Formation are exposed at the surface within the Indian Knob Valley. Of this area, approximately 400 acres are exposed on slopes greater than 30 percent, which largely precludes infiltration of precipitation. A total of 350 acres of exposed Edna member are present on soils consisting of various loamy sands with drainage classes described as somewhat excessively drained, with slopes between 9 and 30 percent. A total of 30 acres of somewhat excessively drained soils are present on slopes between 5 and 15 percent. The remainder of the exposed outcrop is located in well drained loamy sands with slopes between 5 and 9 percent. A summary of the soil, slope and drainage properties of these soils is presented as Table V-A.1. Price Canyon General Plan Update, SOI Change, Annexation and Specific Plan Program EIR V-A Groundwater Resources Page V-A8

12 Table V-A.1: Soil Classification and Percolation Estimates in Outcrop Areas of the Pismo Formation overlying the Indian Knob Valley Aquifer Outcrop Soil Acres Est. Percolation Edna Various loamy sand, 9 to 30 percent slopes % Edna Arnold loamy sand, 5 to 15 percent slopes 30 12% Edna Elder sandy loam, 5 to 9 percent slopes % Edna Other areas, slope > 30 percent slopes 400 8% Total Gragg Pismo loamy sand, 9 to 30 percent slopes Gragg Various loamy sand, 5 to 15 percent slopes Gragg Elder sandy loam, 2 to 9 percent slopes Gragg Other areas, slope > 30 percent slopes Total PISMO FORMATION IN THE OAK PARK AREA Previous investigations have identified the existence of a dual aquifer system in the Pismo Formation aquifer south of the study area, in the Oak Park area (Fugro, 2007; Cleath and Associates, 2004). The two aquifers are separated by a thick clay-rich aquitard. The southeastern portion of the study area overlies the deep Oak Park aquifer, the areal extent of which is presented on Map V-A.2. The relationship of the Oak Park shallow and deep aquifers and the project study area is shown on Map V-A.2, and Figures V-A.3 and V-A.4. The geologic map classifies most of the surface of the Oak Park area as the Squire member of the Pismo Formation, but notes that there is no clear lithologic distinction between Edna and Squire Members in this area (Hall, 1973). The sand and clay layers identified on Figures V-A.3 and V-A.4 were derived from the interpretation of borehole logs in the Oak Park area (Fugro, 2007). Hall (1973) shows the extension of the same synclinal-anticlinal structure present in the Indian Knob Valley area bisecting the Oak Park area and trending northwest to southeast, as shown on Plate 2. Fugro (2007) describes the syncline as plunging towards the center of the Oak Park area from Price Canyon and Arroyo Grande Creek Valley. The synclinal structure forms a sedimentary basin in which groundwater is contained within permeable (typically sand rich) layers, forming aquifers separated by relatively impermeable clay-rich beds. The Oak Park Shallow Aquifer - The shallow aquifer is composed of sand, clay, and sandy clay layers, with occasional gravels. This aquifer reaches its greatest depth at the center of the synclinal structure, corresponding to a thickness of 750 feet as shown on Figure V-A.3. Most of the private domestic supply wells in this area are screened in the shallow aquifer. Water levels Price Canyon General Plan Update, SOI Change, Annexation and Specific Plan Program EIR V-A Groundwater Resources Page V-A9

13 within the shallow aquifer are quite variable, ranging from 20 to 180 feet below ground surface, depending on the stratigraphic layers that the well screen intersects. None of the wells in the Price Canyon Planning Area penetrate and extract groundwater from the Oak Park shallow aquifer, and no interference impacts between the study area and the Oak Park shallow aquifer wells will occur. The Oak Park Deep Aquifer- The deep aquifer is composed of fine sand, silty sands, and clays, with occasional gravels. The aquifer thickness is based on data from water and oil well logs and is 250 to 350 feet in thickness, reaching a depth of more than 1,400 feet below sea level at the center of the basin (Figures V-A.3 and V-A.4). The aquifer outcrop or subcrop pattern, where the surface expression of the sediments that comprise the deep aquifer reach the ground surface, is shown on Plate 2. Water levels in wells that penetrate the deep aquifer at depth are apparently under hydraulic pressure. In wells with screened intervals several hundred feet below ground surface, water levels are near ground surface (Fugro 2007). The Godfrey wells penetrate and extract groundwater from the Oak Park deep aquifer, but the Spanish Springs South Ranch wells do not (Map V-A.2 and Figure V-A.3). The Aquitard- The clay-rich aquitard unit between the shallow and deep aquifers is a sandy clay or green sand and clay. Where sand is present in boreholes that penetrate the clay-rich zone, the sand is generally very fine to fine-grained. The aquitard is 400 to 700 feet in thickness (Figure V-A.3). The thickness of the unit and abundance of clay-rich horizons within the unit retards hydraulic communication between the shallow and deep aquifers. AQUIFER PARAMETERS A summary of the Indian Knob Valley aquifer and Pismo Creek alluvial aquifer parameter data is given in Table V-A.2 Aquifer Parameter Summary. Insufficient data exists to determine the aquifer parameters for the Godfrey wells. However, previous work conducted on the Oak Park deep aquifer indicates hydraulic conductivity values in the range of approximately 4 to 9 feet/day (Fugro, 2007), which is somewhat lower than the equivalent values calculated for the Indian Knob Valley aquifer. The hydraulic conductivity values for the alluvial aquifer are atypically low for alluvium, but reflect the relatively fine-grained nature of the aquifer materials and the thin saturated thickness. The values also correspond well to the relatively low discharge rate capabilities of the alluvial wells. Price Canyon General Plan Update, SOI Change, Annexation and Specific Plan Program EIR V-A Groundwater Resources Page V-A10

14 Table V-A.2: Aquifer Parameter Summary Well Aquifer Date of Test Pumping Rate, Q gpm Drawdown one log cycle, ds feet Theoretical Long-term Drawdown, feet Transmissivity feet 2 /day Saturated Thickness feet Hydraulic Conductivity feet/d West Well North Ranch #10 Indian Knob Valley, Edna Member Indian Knob Valley, Edna Member June 2003 June 2003 #1 Alluvium August 1999 #4 Alluvium August 1999 #7 Alluvium August 1999 #9 Alluvium August 1999 #10 Alluvium August 1999 #11 Alluvium August N/A 2, N/A 2, * N/A * 75 74* N/A , * * N/A * 18 14* N/A * 38 9* N/A * 26 24* N/A * 20 * Theoretical long-term value Price Canyon General Plan Update, SOI Change, Annexation and Specific Plan Program EIR V-A Groundwater Resources Page V-A11

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20 AQUIFER CHARACTERISTICS This analysis summarizes the availability of groundwater from on-site wells as a source of water for the project. Information from a total of 18 groundwater wells on the project site was provided to us by the PCI and Spanish Springs Ranch Planning Area landowners. Based on the information provided, a search of Department of Water Resources well logs, and site visits and inspections, the available information on the site wells is summarized in Table V-A.3 Summary of Groundwater Supply Wells. The summary table includes wells from the Spanish Springs North and South Ranch and the Godfrey property, only; although some wells are known to exist on the Big Bird property, the information was not provided and is not included in this analysis. A summary of the short-term pumping capacities of the aquifers is shown on Table V-A.4 Summary of Short-term Groundwater Pumping Capacity. The total amount of water available to the project on a perennial basis is limited not by the short-term (instantaneous) pumping capacities of each well, which are known to varying degrees, but by the overall recharge to each aquifer system, regional groundwater levels, and demand from competing users. The available supply of water from groundwater is estimated to be approximately 110 to 130 afy (40 to 60 afy from the Indian Knob Valley aquifer and 70 afy from the alluvium, adjusted from a gross volume of 170 to 220 afy in order to maintain minimum stream flow for habitat), as detailed following. Price Canyon General Plan Update, SOI Change, Annexation and Specific Plan Program EIR V-A Groundwater Resources Page V-A17

21 Table V-A.3 - Summary of Groundwater Supply Wells Source: Cleath and Associates Well Name/ Number Aquifer Location Operational Pumping Rate (gpm) Drought Pumping Rate (gpm) Well Depth, (feet) Year Drilled T32S/ R12E-1R2 Alluvial Price Canyon #1 Alluvial Price Canyon #4 Alluvial Price Canyon #7 Alluvial Price Canyon #9 Alluvial Price Canyon #10 Alluvial Price Canyon #11 Alluvial Price Canyon South Ranch #1 South Ranch #2 Well A Test #4 Well B Hole North Ranch #2 West Well North Ranch #10 Miguelito? Miguelito? Indian Knob Valley (Edna) Indian Knob Valley (Edna) Indian Knob Valley (Edna) Alluvial Indian Knob Valley (Edna) Indian Knob Valley (Edna) Godfrey #1 Oak Park (Edna) Godfrey #2 Oak Park (Edna) Godfrey #3 Oak Park (Edna) SE Corner, South Ranch NE Corner, South Ranch North Ranch, Lot 16 North Ranch North Ranch, Lot 15 North Ranch Along Creek Northwest Corner, North North Ranch, Lot 16 Eastern Godfrey Eastern Godfrey Eastern Godfrey No Data No Data No Data No Data Airlifted 15 No Data Airlifted 30 No Data Airlifted 50 No Data Air lifted 200 No Data Airlifted 50 No Data Airlifted 30 No Data 53 Unknown 150 No Data No Data No Data No Data No Data Price Canyon General Plan Update, SOI Change, Annexation and Specific Plan Program EIR V-A Groundwater Resources Page V-A18

22 Table V-A.4 - Summary of Short-term Groundwater Pumping Capacity Aquifer Spanish Springs Alluvial Wells Short-term Pumping Rate (gpm) 180 Indian Knob Valley Wells 250 Spanish Springs South Ranch (Miguelito) Wells Godfrey (Oak Park Deep Aquifer) Wells INDIAN KNOB VALLEY AQUIFER The Indian Knob Valley aquifer comprises the water-producing horizons of the Gragg and Edna members of the Pismo Formation, as shown on the geologic cross sections (Figures V- A.1-5). However, the project wells penetrate and extract groundwater from a limited portion of the aquifer, and only from the Edna member. Thus, the total recharge to the aquifer and the amount of recharge to the aquifer available that the project wells can pump, are two very different amounts. Given the limited recorded history of use of the Indian Knob Valley wells, a lack of consistent, regular water level measurements, no stream flow gage records, and other factors, an annual aquifer yield for the Spanish Springs North Ranch wells that pump from the Indian Knob Valley aquifer is from 40 to 60 afy. This estimate can be refined with several years of recorded data, particularly well water levels and volumes of produced groundwater. PISMO CREEK ALLUVIAL AQUIFER (SPANISH SPRINGS RANCH) The availability of groundwater in the Pismo Creek alluvial aquifer for extraction and use by the project is variable. By the nature of a shallow, seasonal alluvial aquifer like the Pismo Creek alluvium, the amount of groundwater available to wells is highly dependent on the rainfall in any one year. Deep, basin-type aquifers (such as the Edna Valley Groundwater Basin or the Santa Maria Groundwater Basin) can withstand occasional years of below average rainfall through utilization of groundwater in storage, to be replenished during years of above average rainfall. Shallow alluvial aquifers such as the Pismo Creek aquifer do not have the luxury, however, of a large volume of groundwater in storage, so years of poor rainfall results in relatively immediately declining water levels and/or well production. On the positive side, however, these types of aquifers do not enter into prolonged or chronic overdraft, because even a single year of normal or above normal rainfall will generally result in full system recharge and replenishment. Basin-type aquifers or even fractured-rock aquifers like the Indian Knob Valley aquifer and the Oak Park deep aquifer can draw from groundwater in storage during dry years, thus the perennial yield of the aquifer can be based on average annual recharge amounts. However, as discussed above, because small alluvial aquifers like the Pismo Creek alluvium have limited groundwater in storage to act as a drought buffer, the recharge to the aquifer during drought conditions is the best means to estimate the yield of this source. Price Canyon General Plan Update, SOI Change, Annexation and Specific Plan Program EIR V-A Groundwater Resources Page V-A19

23 Absent a history of stream flow records and water level measurements from alluvial wells, the available water can best be estimated by calculating the amount of groundwater in storage available to the wells, plus the amount of base flow that can be utilized. It appears that the Edna Valley Groundwater Basin is not a source of recharge to the alluvium in the Spanish Springs Ranch area. Subsurface base flow from the Edna Basin is restricted by the Edna fault that forms the southern boundary of the Basin. Furthermore, during low rainfall periods, Pismo Creek is typically dry in certain reaches between the Basin edge and the northern edge of the Spanish Springs Ranch. The stream flow that does occur in the creek through Spanish Springs appears to originate in springs and subsurface base flow from the surrounding bedrock. The volume of this base flow was estimated by Balance Hydrologics (2007) and Cleath and Associates (2008d). A reasonable estimate of the volume of base flow in the creek that provides a source of recharge to the project alluvial wells is approximately 70 afy. As described earlier, the total volume of groundwater in storage in the alluvium in the study area is estimated to be approximately 500 to 600 acre-feet (af). The entire volume of groundwater in storage cannot be pumped from the aquifer from wells, so a reasonable volume of the groundwater in storage available to the shallow wells is estimated to be 100 afy to 150 afy. Thus, the total volume of groundwater available to the Pismo Creek alluvial wells in the Spanish Springs Ranch area is approximately 170 to 220 afy (200 afy: afy groundwater in storage plus 70 afy base flow). It is important to note that this estimate of alluvial aquifer yield does not take into account any potential environmental demand. Heavy pumping of the alluvial wells will reduce groundwater in storage, which will induce recharge by base flow and likely reduce surface flow. Thus, the volume of water available to the alluvial wells must be balanced by the environmental demand. ALLUVIAL AQUIFER YIELD ENHANCEMENT The yield of the alluvial aquifer could potentially be enhanced through a managed recharge and recovery concept, whereby a source of imported water is introduced into the creek above and recovered by the Spanish Springs alluvial well field. The source of the imported recharge water could be reclaimed water from the City of Pismo Beach s wastewater treatment plant as detailed elsewhere in the EIR. The concept of aquifer enhancement of an alluvial aquifer has been successfully implemented throughout the state, including at least two situations in San Luis Obispo County. Recharge into the Salinas River from wastewater treatment plant percolation pond facilities in Atascadero and Templeton is subsequently extracted for beneficial use by downstream municipal wells. With adequate travel time (usually measured in terms of distance from the source), the recharge water can be recovered and used for potable demand purposes, as regulated by the Regional Water Quality Control Board and the State Department of Public Health. The regulations for recovery of the recharged water vary based on the degree of treatment, the intended use of the recovered water, and the hydraulic conductivity of the aquifer. This concept has the potential advantage of maintaining environmental demand in the creek while enhancing the yield of the alluvial wells. Price Canyon General Plan Update, SOI Change, Annexation and Specific Plan Program EIR V-A Groundwater Resources Page V-A20

24 WATER QUALITY The water quality data indicate that water produced from the Edna member wells meet drinking water requirements. Alluvial wells generally meet primary drinking water standards, but exceed secondary standards. 3. Impact Analysis Environmental Impact Significance Criteria The CEQA Guidelines indicate that a project would have a significant effect on the environment if it would: Substantially deplete groundwater supplies or interfere substantially with groundwater recharge such that there would be a net deficit in aquifer volume or a lowering of the local groundwater table level (e.g., the production rate of pre-existing nearby wells would drop to a level which would not support existing land uses or planned uses for which permits have been granted). This significance threshold is applied in the following way in this EIR section: The Proposed Project would have a significant impact if there would be a net deficit in aquifer volume or a lowering of the local groundwater table level that results in the production rate of pre-existing nearby wells would drop to a level which would not support existing land uses, or If there would be a net deficit in aquifer volume or a lowering of the local groundwater table level that results in stream flow in Pismo Creek being reduced to a level that adversely impacts the aquatic habitat. The second significance criterion applies to biotic resources. However, due to the interrelationship of groundwater hydrology to the habitat and the specific geologic and hydrologic analyses undertaken to evaluate this topic, the environmental analysis is presented in this section rather than section IV.C Biological Resources. Proposed Use of Groundwater Resources The PCSP proposes to utilize groundwater from two aquifers: the Indian Knob Aquifer and the Pismo Creek Alluvium aquifer. The Indian Knob aquifer wells have been utilized by the Spanish Springs owners to establish vineyards and implement road construction on the north ranch over the last several years. Based on pumping records, the estimate extraction has been about 75 afy for these activities. Grape establishment requires greater than the projected long term demand of 0.5 AFY per acre of vineyard and short-term tract construction demand for water has now essentially ceased. Agricultural activities at Spanish Springs include about acres of planted and planting in-progress vineyards, and plans for another 154 to acres of vines, totaling 280 acres 1. 1 During the course of PCSP and EIR preparation in , various studies and planning documents have referred to 250, 280 and 350 acres of planned vineyards. The 280 acre figure is based on the November 2009 project description provided by the landowners. Price Canyon General Plan Update, SOI Change, Annexation and Specific Plan Program EIR V-A Groundwater Resources Page V-A21

25 As discussed in the PCSP appendix Agricultural Water Supply Program, October 28, 2009, water demands have been estimated for the individual phases and full buildout of the vineyards. Seasonal extraction needs have also been estimated based on extrapolations of actual experience at the North Ranch Spanish Springs Vineyards. Over the period June 2008 through May 2009, daily extractions from the Indian Knob basin for routine drip irrigation and spray frost protection were recorded. There has been just under 75 acre feet of irrigation demand over slightly more than 100 existing acres of vines. During the April-October growing season, about 93% of total irrigation demand will be used. Remaining water use during the November-March period is small due to the dormant nature of the vines, and the seasonal rainfall occurring during these months at varying frequency. The PCSP includes a strategy for providing irrigation water to the existing vineyards and planned vineyard expansions in Phases 2 thru 4. This strategy includes converting all current agricultural water supply from the Indian Knob aquifer to a combination of groundwater extractions from the Pismo Creek Alluvial aquifer, and use of reclaimed water as described in sections l. Project Description and V.B Municipal Water Supply. As described there, reclaimed water can be applied as drip irrigation to the vines, supplied by the reclaimed water infrastructure and held in storage ponds. The use of reclaimed water in a recharge and recovery program is not required to meet he anticipated irrigation demand. The Indian Knob aquifer is planned to continue to supply irrigation water for the vineyards in the short term. The ultimate demand for vineyards when the planned buildout is reached would be 140 afy for 280 acres of vines. There are three wells located on the South Ranch near Pismo Creek that are the primary candidates for use in the groundwater extraction program. These wells are noted as wells #1, #4 (both west of the railroad tracks) and #11 (east of the railroad tracks) as shown on Figure V- A.2 and in the Technical Appendix. The Cleath Harris Geologist study suggested that Well #4 was best suited for continuing extractions, and Well #11 was also viable for this purpose. It was noted that well #1 was located closer to the upper reach of the creek in this area of the South Ranch, and during test pumping had a more pronounced effect on creek pooling and stream flow in this upper reach when the testing was done (August, 2009). For these reasons, the proposed program calls for wells #4 and #11 to provide the primary groundwater extraction from the alluvium. These wells individually have a capacity to draw about 60 gallons per minute (gpm). Assuming the operation of these wells are coordinated to yield a combined 60 gpm constant draw, this would yield 0.13 cubic feet per second (cfs), or 86,400 gallons in a 24-hour period, and about 2,592,000 gallons in a 30-day month. This yield (at about 7.95 acre feet per month or 95 acre feet over 12 months (AFY) is recognized to exceed the volume needed to maintain stream flow as discussed further following. Based on the Cleath report, extractions are proposed to be limited from the Alluvial GW Basin to no more than 0.20 cfs (89.76 gallons per minute) or a total of 70 acre feet of water during the December - May period (6 months). Therefore, with well extractions from the Pismo Creek Alluvial GW Basin limited to the December-May window, it is proposed to withdraw up to 70 acre feet at a rate of around 80 gallons per minute. Price Canyon General Plan Update, SOI Change, Annexation and Specific Plan Program EIR V-A Groundwater Resources Page V-A22

26 Extractions from the alluvium would be discontinued from June through November in order to insure lower flow conditions typically prevalent within Pismo Creek during this period would not be impacted by irrigation well extractions. Agricultural irrigation requirements are proposed to be augmented by the City s Reclaimed Wastewater Reuse program to provide the balance of irrigation supplies needed. To accomplish this, a phased approach to implementing this agriculture water supply program is proposed. Each step in this sequence is designed to also allow an environmental monitoring program to occur parallel to each step in the water supply development and use sequence. This monitoring program is envisioned to include: Water extraction records (for each well) including volume and water levels in the well; Permanent stream flow gauge installation(s) to monitor stream flows monthly; Bi-annual biological monitoring to assess creek conditions and habitat effect, if any; Annual reports summarizing data and findings to City-County-Resource Agencies. The proposed sequence of steps to implement vineyard buildout and irrigation supply is as follows: Step #1: Conversion of the North Ranch vineyards from Indian Knob supplies to Alluvial supplies can occur during the Phase 1 Master Plan project. This would be accomplished by establishing additional water distribution lines and pump stations on the South Ranch to deliver Alluvial water supplies to the North Ranch irrigation ponds presently serving the vineyards. Step #2: Prior to the conversion of irrigation source from the Indian Knob aquifer to the Alluvial aquifer, a Monitoring Agreement shall be entered into with the vineyard developers, City of Pismo Beach and the appropriate resource agencies to implement a mutually acceptable aquifer monitoring program. Step #3: During planning for the addition of treatment equipment at the City s WWTP to produce reclaimed water, similar analysis of the size and placement of South Ranch reclaimed water delivery lines and storage will be completed. The open storage (lakes) on the South Ranch will be designed to hold an amount of water needed to cover the projected seasonal shortfalls in monthly well pumping and ultimate agricultural water demands. The placement of these storage reservoirs, and the timing of their improvement, will also be detailed in this step. Step #4: Concurrent with Phase 2 residential and commercial development, South Ranch reclaimed water delivery lines and storage lakes will be installed to supply irrigation service to both the South Ranch and North Ranch vineyards. Step #5: Phase 2 and Phase 3 vineyard installations shall be timed to coincide with the availability of reclaimed water supplies. PROPOSED GROUNDWATER RECHARGE AND RECOVERY PROGRAM As described in section l Project Description, the City anticipates pursing a groundwater recharge and recovery program (GRRP) utilizing reclaimed water to recharge the Pismo Creek Price Canyon General Plan Update, SOI Change, Annexation and Specific Plan Program EIR V-A Groundwater Resources Page V-A23

27 Alluvium and extracting the water downstream for potable water use as described in draft General Plan policy LU-R-11 Beneficial Reuse of Reclaimed Water in the Pismo Creek Alluvial Aquifer. Additional information and discussion is presented in sections V-B Municipal Water Supply and IV-D Drainage, Flooding and Water Quality. As described above, there are several wells that tap this alluvium on the Spanish Springs south ranch. As these wells are being pumped, some recharge occurs from the stream flow, however, one of the limitations to the amount of water produced from these wells is the minimum flow required in the stream to support riparian habitat. In order to preclude this from occurring while alluvial wells are being pumped, highly treated effluent from the Pismo Beach wastewater plant could be discharged to the stream channel, or percolation ponds and recharge the alluvium. The Price Canyon Planning Area Constraint Study (2009) presented the analytical and planning rationale for the concept of a GRRP that would utilize the City reclaimed water supply (that is planned to have infrastructure extended to supply the Planning Area for irrigation) to recharge the alluvium to allow groundwater pumping of alluvium wells at rates that would exceed the Planning Area needs and provide an additional source of city water supply. The amount of recharge and pumping would be designed to ensure adequate stream flow for aquatic habitat in the creek. Environmental Impacts INDIAN KNOB AQUIFER The proposed use of the Indian Knob groundwater wells is temporary, to continue to irrigate existing vineyards. Preliminary indication of the yield of the Indian Knob wells in the long term is 40 to 60 AFY. The extraction rate for several years has been closer to 75 AFY to establish 126 acres of vineyard. In the long-term, this rate of extraction has the potential to adversely effect groundwater levels in pre-existing nearby wells. This effect is presumed to be potentially significant if continued into the long-term, although the location of Spanish Springs wells is near the edge of the Indian Knob aquifer and would therefore affect wells in the deeper portions of the aquifer less than otherwise, and the actual production characteristics of nearby wells are not known. Impact GW-1: Based on available data, the continued pumping level of 75 AFY for Spanish Springs north Ranch vineyards could result in a significant impact on groundwater resources. POTENTIAL IMPACTS OF THE AGRICULTURAL IRRIGATION PROGRAM As discussed above, the implementation of a recharge and recovery program for beneficial reuse of reclaimed water must take into account the effects of the recharge and subsequent pumping on stream flows. As described in section IV-C Biological Resources, sensitive species in the creek include steelhead trout, and downstream in the creek estuary, the Tidewater Goby. Both species would be potentially affected by changes in water quality that might result from modifying the stream underflow characteristics by recharge using reclaimed water. Discussions of water quality are contained in sections IV-B and IV-D of the EIR. More important, these species require adequate stream flow. There has not been a long history of Price Canyon General Plan Update, SOI Change, Annexation and Specific Plan Program EIR V-A Groundwater Resources Page V-A24

28 stream flow gaging in Pismo Creek, therefore the needed environmental base flow for these species has not been comprehensively documented. In order to determine the potential effects on stream flow that could result from pumping alluvium wells for agriculture, Cleath Harris Geologists (CHG) performed field investigations in August 2009 to more precisely define the stream morphology and alluvium characteristics and measure and record the effects of pumping. The CHG analysis was peer reviewed by Fugro West and Balance Hydrologic. The following narrative distills the investigation findings and peer review observations 2. The Cleath-Harris field investigation included descriptions of the streambed and alluvial aquifer, a pumping test of a single alluvial water well, the monitoring of water levels in other wells and in the creek during the performance of the pumping test, and a brief discussion of groundwater and stream interaction and recharge. Existing wells were used for the pumping test and monitoring network. Several water well logs are available for use to describe the geometry and extent of the stream system and alluvial aquifer. The system that is described consists of a relatively well-defined creek system that varies in thickness and width. The creek is incised in places into bedrock, which forms the stream bed throughout a stretch of the creek and has rather significant implications with respect to aquifer/stream flow interaction and stream recharge. The conceptual model described by Cleath-Harris, and which appears reasonable based on inspection of the well logs and our field reconnaissance visits, is one in which surface and subsurface flow enters the area in the creek and channel from the north, hits the bedrock channel portion of the system, and then either flows across the bedrock as surface flow or deflects laterally into the alluvial fan complex as bank storage. Groundwater that has entered the alluvial fan complex as bank storage through lateral or horizontal infiltration then drains slowly into the creek (and subsurface) downstream of the bedrock channel. The small alluvial fan complex adjacent to and east of the bedrock channel has apparently formed through sediment flow and deposition from a tributary drainage east of Pismo Creek. Groundwater flow through the fan complex is westward toward the creek until flow is impeded by the bedrock barrier in the channel, then southward along the general gradient of the creek system. Wells #4 and #11 are well-positioned to maximize the capture of the bank storage and groundwater flow in the alluvial fan materials. Downstream of the alluvial fan (and downstream of the bedrock-incised stream channel), the alluvial aquifer apparently becomes much finer-grained in what Cleath-Harris describes as an alluvial floodplain. Although the stream channel is still well-defined and incised, the stream bed consists of alluvial materials to an unknown depth and is likely in continuous contact with groundwater in the adjacent floodplain alluvial aquifer. It is within this stretch of the creek, in particular, that the potential impacts of extracting groundwater from the alluvial aquifer may occur. 2 The narrative combines information from Cleath Harris Geologists, Stream Characterization and Impact Studies and Well Testing Program for the Pismo Creek Alluvial Aquifers, October 23, 2009: Fugro West Review of Pismo Creek Study Conducted by Cleath- Harris Geologists, Price Canyon General Plan Update, Annexation, SOI Change and Specific Plan Program EIR January 20, 2010; and Balance Hydrologic, Review of Cleath-Harris Geologists Stream Characterization and Impact Studies and Well Testing Program, Pismo Creek Alluvial Aquifers, Price Canyon Price Canyon General Plan Update, SOI Change, Annexation and Specific Plan Program EIR V-A Groundwater Resources Page V-A25