DRINKING WATER SOURCE PROTECTION PLAN For The SNOW CANYON WELL FIELD PREPARED FOR ST. GEORGE CITY WATER SYSTEM NO. 27015 August 2011 Prepared by: Table of Contents SOURCE PROTECTION PLAN EXECUTIVE SUMMARY………………………………………………………...1 1.0 Introduction …..…………………………………………….…………………2 2.0 Delineation Report …..…………………………………………………….….3 3.0 Inventory of Potential Contamination sources ………………………………..10 4.0 Assessment of Potential Contamination source Hazards………………………14 5.0 Management Program for Existing Potential Contamination Sources ………..14 6.0 Management Program for Future Potential Contamination Sources ………….14 7.0 Implementation Schedule ……………………………………………………..14 8.0 Resource Evaluation …………………………………………………………..15 9.0 Recordkeeping …………………………………………………………………15 10.0 Contingency Plan …………………………………………………………….17 11.0 Public Notification ……………………………………………………………21 12.0 Waivers ………………………………………………………………………22 References Drinking Water Source Protection Plan Snow Canyon Well Field i APPENDICES Appendix A Figures 1-5 Appendix B Well Logs Appendix C Consumer Confidence Report Laboratory Report – Certificate of Analysis Use Waiver Certification Statement Letter to Snow Canyon State Park Drinking Water Source Protection Plan Snow Canyon Well Field ii DRINKING WATER SOURCE PROTECTION PLAN EXECUTIVE SUMMARY Currently the City of St. George owns and operates 5 wells and Santa Clara City owns and operates 2 wells which are located within the Snow Canyon State Park with the surrounding lands being under the control of the Utah State Division of Parks and Recreation or BLM. Currently the protection zones for this well field are defined by the 2 mile radius delineation procedure. Since the 2 mile radius procedure is a more conservative approach and may encompass a larger source protection management area than may be required, the City of St. George has retained Alpha Engineering to determine and define the source protection zones using the preferred delineation procedure for the well field and prepare the Drinking Water Source Protection Plan (DWSPP) to reflect the findings of the procedure. This report analyzes the well field, based on the existing data for the 7 wells. The results of the analysis shows that all zones for the St. George City wells are within the Snow Canyon State Park and BLM and the zones for Santa Clara City wells are within the Snow Canyon State Park, BLM and private ground owned by Diamond Valley Properties LLC. It was determined that there are currently no potential contamination sources within the well field. The City of St. George will continue correspondence with the State Parks and Recreation and BLM offices yearly to inform them of the municipal water sources and request assistance in ground water protection for these sources. 1.0 INTRODUCTION 1.1 SYSTEM INFORMATION St. George City has retained Alpha Engineering to complete a Drinking Water Source Protection (DWSP) Plan for this portion of their public water system No 27015. The Delineation Report portion presents the source protection zone delineations for the Snow Canyon Well Field which consists of 7 wells (St. George City Wells #2, #3, #3A, #4, #5 and Santa Clara City Wells #1 and #2) The 7 wells will be referred to as the Snow Canyon Well Field throughout the report. This report has been prepared and is submitted to satisfy the Source Protection requirements in accordance with Section R309-600, latest revision October 29, 2003 for new wells and springs and being submitted for the St. George City Wells 2, 3, 3A, 4 and 5. It should be noted that the Santa Clara City wells have been included in the analysis because they influence the well field and should be considered for defining the delineation zones. Drinking Water Source Projection Plan 1 Snow Canyon Well Field Water System Name, Number and Address City of St. George Water System No. 27015 175 East 200 North St. George, UT. 84770 (435) 635-9442 1.2 SOURCE INFORMATION This Drinking Water Source Protection Plan is being submitted for the Snow Canyon Well Field. The wells are located within the Snow Canyon State Park, approximately 6 miles northwest of the City of St. George, Utah, as indicated on Figure 1 in Appendix A. The locations of the wells are more specifically described in the following table. TABLE 1 WELL LOCATIONS Description Well Location St. George City Snow Canyon Well #2 S 711 ft. W 1429 ft. from N4 cor. Section 16 T41S R16 W St. George City Snow Canyon Well #3 N 1996 ft. W 2038 ft. from S4 cor. Section 9 T41S, R16W St. George City Snow Canyon Well #3A N 1996 ft. W 2038 ft. from S4 cor. Section 9 T41S, R16W St. George City Snow Canyon Well #4 N 4196 ft. W 1853 ft. from S4 cor. Section 9 T41S, R16W St. George City Snow Canyon Well #5 S 245 ft. E 420 ft. from S4 cor. Section 16 T41S, R16W Santa Clara City Snow Canyon Well #1 N 516 ft. E715 from SW cor. Section 4 T41S, R16W Santa Clara City Snow Canyon Well #2 N 1670 ft. E 540 ft. from SW cor. Section 4 T41S, R16W 1.3 DESIGNATED PERSON In accordance with the State Rules, Section R309-600-5, the designated person in charge of the St. George City water system is: Mr. Barry Barnum Water Services Department City of St. George 175 East 200 North St. George, Utah 84770 Drinking Water Source Projection Plan 2 Snow Canyon Well Field 435-627-4800 (office) 2.0 DELINEATION REPORT This Delineation Report has been prepared to fulfill the requirements of Section R309-600-9, Delineation of Protection Zones and Management Areas, as required by the Drinking Water Source Protection Rule, revised October 29, 2003. The purpose of this report is to determine the source protection zones for the Snow Canyon Well Field. The wells are being treated as a wellfield in order to model potential interference from each other and to map the calculated delineation zones as required by the Drinking Water Source Protection Rule. The State rules allow for two delineation procedures; one being the two-mile delineation and the second being the preferred delineation procedure. This report utilizes the preferred delineation procedure. The four zones identified in this procedure are: Zone 1: The area located within a 100-foot radius of the wellhead Zone 2: The area located within a 250-day groundwater travel time to the wellhead. Zone 3: The area located within a 3-year groundwater travel time to the wellhead. Zone 4: The area located within a 15-year groundwater travel time to the wellhead. Figure 4 in Appendix A shows the well location and delineation zones for each of the wells in this report. 2.1 GEOLOGIC DATA STRATIGRAPHY Figure 2, (after Willis and Higgins, 1996) shows the geology of the Snow Canyon area. The area includes 5 wells owned by St. George City and 2 wells owned by Santa Clara City. Shallow alluvial, colluvial, and eolian deposits overlie the well sites. These deposits are generally less than 20 feet thick and consist largely of silty sand and fine to coarse grained sand deposits with occasional basalt/sandstone cobbles and boulders. The alluvial, colluvial, and eolian deposits are underlain by the Jurassic Age Navajo Sandstone. The Navajo Sandstone is massive, crossbedded, and fine to medium grained. Grains consist of frosted quartz poorly to moderately cemented with calcareous and siliceous cement. Where poorly cemented, the sandstone is quite friable. Moderate to highly jointed areas are common. Thick crossbed sets are prominent. The Navajo Sandstone is about 2,500 feet thick in the Snow Canyon area. STRUCTURE The Snow Canyon area lies within the transitional zone between the Colorado Plateau and the Basin and Range physiographic Provinces. The Basin and Range province is characterized by east-west extensional tectonics that form long, straight, north-south trending mountain ranges Drinking Water Source Projection Plan 3 Snow Canyon Well Field with intervening basins. Normal faulting and widespread igneous activity during the Miocene (15 million years ago to present) were the dominant geologic processes. The transitional zone between the two provinces includes two major down-to-the-west normal faults (Hurricane and Gunlock-Grand Wash) that effect the transition from the Colorado Plateau to the Basin and Range. The area lies on the intermediate block created and bounded by the Hurricane fault zone on the east and the Gunlock-Grand Wash fault on the west. Strata west of the Gunlock-Grand Wash fault are complexly deformed, while strata to the east, including the Snow Canyon area, are only slightly deformed. The transition zone has also been influenced by Late Cretaceous compressional events that produced the Virgin anticline. Regional folding, faulting, and volcanics have all affected the area. The most prominent structural features in the area are the numerous joints and factures within the Navajo Sandstone. Generally all competent strata are fractured, but the most prominent joints are in the massive sandstone beds. Willis and Higgins (1996) indicates that within the Snow Canyon area joints set are parallel, widely spaced, high-angle, with overall trends to the north and northeast. Some of these trends are several miles in length. These large, prominent joint patterns are shown by “lineament” symbols on Figure 2. 2.2 WELL CONSTRUCTION DATA The Snow Canyon Wells are located within the Snow Canyon State Park as shown on Figure 1B in Appendix A. Well logs for all seven wells are included in Appendix B and the following tables summarize the well data. TABLE 2 WELL DATA SUMMARY St George Well St. George St. George St. George DESCRIPTION #2 Well #3 Well #3A Well # 4 Well Casing Diameter (inches) 16 16 16 16 Total Depth of Well (feet) 830 1,000 1,160 800 Well Screen & Perforation Not Slot (1/16” x 3”) SS 304 (0.30”) Type available Not available Depth and Length of Screen Not with Perforated Interval(s) 350’-830’ 360’-1160’ Not available available (feet) Grouted Length (feet) 0’ - 100’ 0’ – 100’ 0’ – 115’ 0’ – 100’ Welded Welded Steel Welded Steel Casing type Steel Not available Drinking Water Source Projection Plan 4 Snow Canyon Well Field St George Well St.