Table of Contents
Figure 1.1: Arizona’s Watersheds ……………………………….………………..,……..4
Figure 1.2: Sub-Watershed Region………………….. ..…………………….……….…5
Figure 2.1: Map of Francis Creek ………………………………………………….……6
Table 2.1: Peak flows of Francis Creek………………………………………….………7
Table 2.2: Peak flows of Burro Creek ………………………………………..…………8
The purpose of this project is to identify and map the potential damage to the Hillside Mine waste repository cap in the event of a catastrophic flood. Due to recent changes in yearly weather patterns the possibility of a 500 year event is greater.
Arizona has been in a state of drought for fifteen years. The potential for wildfires is greatly increased versus years with average precipitation. Given that the Boulder Creek watershed extends into higher forested elevations, the possibility for fire damage on Bozarth mesa may also be a concern. Flash flooding is much more likely in areas affected by devastating fires.
Another concern is from higher than average precipitation. Arizona is expected to have one of the strongest El Nino weather patterns on record towards the end of the 2015 winter . Additional precipitation could create oversaturation of soils, increasing the chance for localized flooding in the area. There is a direct relationship between rainfall and erosion on the cap. The goal of this project is to identify the potential and probability of an event causing damage to the Hillside mine cap. If the current containment design is found inadequate, the project may lead to future designs.
The main objective is to keep contaminants, such as heavy metals and acids, out of Boulder Creek. The problem to solve is erosion. The hydraulic study contained within the scope of this project will identify the capacity of erosion to the waste repository cap.
The Hillside Mine is located in the Eureka Mining District in Yavapai County, Arizona. It is located in a mountainous region in the mid-western portion of Arizona. The mine site is five miles north of Bagdad, Arizona, which makes it in close proximity of a small town.
Figure 1.1: Site Location
Boulder Creek is an intermittent stream starting at Camp Wood Mount and extending approximately 37 miles southeast. As seen in figure 1.2, the location of the site is found in the Bill Williams Watershed (#4 on map).
Figure 1.2: Arizona’s Watersheds. 
A closer look at the sub-watershed can be seen in figure 1.3. Before the cap was placed on the Upper Tailings pile, Boulder Creek was in danger of contamination issues due to erosion of the tailings. The current cap safely controls the erosion issues around the creek. The location of this particular site makes it difficult for vehicles to reach area, which acts as a benefit considering recreational activity around the site may cause damage and decrease the lifespan of the engineered cap.
Figure 1.3: Boulder Creek Watershed. 
The project is heavily based in the hydrology field of engineering. Considering that the Boulder Creek watershed is approximately 138 square miles and the flow depends heavily on winter storms and spring snowmelt, hydraulic modeling systems are required. The US Army Corps of Engineers developed a program called HEC-RAS (Hydrologic Engineering Centers River Analysis System) which allows one to perform one-dimensional steady flow, unsteady flow, sediment transport, and water temperature modeling. This modeling system will provide the information needed to anticipate how the stream will act under a catastrophic storm event.
Along with hydrology, the project also includes a geotechnical aspect. Knowing the land and the soil around the stream will lead to more precise erosion results. Since the stream will be analyzed under a 500 year storm, erosion is cause for concern. Too much erosion around the stream could possibly cause failure of the cap, which would release containments into Boulder Creek.
In order to establish the erosion potential of the mine surveying must be performed over a large area. Many hours will be spent gathering the necessary data to map the area. The elevation of the mine is around 3000 feet above mean sea level . In Arizona this elevation can reach temperatures well above 90 degrees Fahrenheit for summer months. Day and night temperatures can vary by 40 degrees. Winter temperatures can drop well below freezing. Crews must be prepared for this environment.
Other potential challenges when conducting this hydraulic study include steep terrain, weather, general access, and contact with plant and animal life. Rain and snow are considerations for access to the mine. The roads are primitive and subject to washouts, and could become too muddy for travel.
The elevation of the mine is around 3000 feet above mean sea level. In Arizona this region contains a range of potential risks. Local wildlife includes venomous snakes, poisonous spiders and scorpions. Cactus and chaparral can create difficulty when traversing rough canyon country. In addition the terrain is steep and rocky which adds difficulty when conducting a survey.
The stakeholders consist of the Bureau of Land management, taxpayers, and local populations of the nearby mine, which in this case is the City of Bagdad. Additionally, any living organism within the watershed may be affected.
The BLM is a stakeholder because they are the organization that is trying to manage land on which the mine is located. The living organisms within the watershed have a stake in this project because their livelihood will be affected if the stream overflows and the cap’s integrity on the mine becomes compromised.
The contamination by mining is directly hazardous to people that participate in recreational activities at the Hillside Mine or Boulder Creek. Secondly, local ranching operations may also be affected by these contaminants. For example, cattle may use the Boulder and Burro Creek as a primary water source. Therefore, it can be said that the contamination released from mining has adverse impacts on almost all direct and indirect stakeholders.
Data gathered included: USGS stream data for Boulder Creek, precipitation data, Site Observations, and Survey data from the critical stream section.
The greatest difficulty in analysis of flows in Boulder Creek is a lack of data. Stream gauges are not established in this particular drainage area. In order to estimate peak flows the adjacent Francis Creek will provide a limited model of Boulder Creek. Francis Creek has an almost identical drainage area and topography. Elevations, vegetation and geology are very alike when compared to the Boulder Creek drainage.
Figure 2.1: Map of Francis creek in relation to site
Unfortunately only four data points are available for peak flows. These values were collected from a USGS stream gauge,which was in service from 1984 to 1994. Table 2.1 shows these peak flows and the date of record.
Table 2.1: Latitude 34°45’42”, Longitude 113°15’54” NAD27
Drainage area 134 square miles
Contributing drainage area 134 square miles
Gage datum 3,260 feet above NGVD29
|Water Year||Date||Gage Height (feet)||Stream- flow (cfs)|
|1990||Aug. 16, 1990||8.38||2,230|
|1991||Mar. 01, 1991||9.42||3,090|
|1992||Feb. 13, 1992||8.77||2,530|
|1993||Feb. 08, 1993||13.68||12,500|
This gauging station will be used to provide a very limited model and will be compared to the Burro creek stream gauge. This gauge is an excellent source of data, however the contributing drainage, which includes both Francis and Boulder Creeks, is 601 square miles. Preliminary comparisons of flows on given dates indicate a direct relationship can be determined between the two gauging stations. The drainage area for Francis and Boulder creek is approximately 4.5 times smaller than the Burro Creek area. When the flood events are compared, the flows are roughly 4.5 times less for the Francis Creek gauging station. This would indicate that the use of the Burro Creek gauging station should provide enough accuracy to extrapolate flows for Boulder creek. Table 2.1 contains the peak flows recorded from 1980 to 2014 for the Burro Creek USGS gauging station.
Table 2.2: Mohave County, Arizona
Hydrologic Unit Code 15030202
Latitude 34°32’30”, Longitude 113°26’40” NAD27
Drainage area 611 square miles
Contributing drainage area 601 square miles
Gage datum 1,880 feet above NGVD29
Year Date Gauge Height CFS
|1980||Feb. 14, 1980||15.60||47,400|
|1981||Sep. 05, 1981||5.00||728|
|1982||Feb. 11, 1982||8.37||5,400|
|1983||Mar. 03, 1983||13.70||30,600|
|1984||Aug. 24, 1984||7.73||3,950|
|1985||Dec. 27, 1984||10.24||12,400|
|1986||Nov. 30, 1985||8.63||6,210|
|1987||Mar. 05, 1987||5.14||565|
|1988||Aug. 27, 1988||8.70||6,410|
|1989||Jan. 05, 1989||5.52||798|
|1990||Sep. 18, 1990||6.13||1,410|
|1991||Mar. 01, 1991||13.71||29,900|
|1992||Feb. 13, 1992||10.87||12,300|
|1993||Feb. 08, 1993||16.30||55,300|
|2004||Sep. 19, 2004||13.15||21,200|
|2005||Feb. 11, 2005||16.48||44,600|
|2006||Sep. 09, 2006||6.63||1,510|
|2007||Sep. 22, 2007||9.04||5,700|
|2009||Dec. 26, 2008||12.86||21,800|
|2010||Jan. 21, 2010||17.32||50,900|
|2011||Mar. 02, 2011||7.07||1,650|
|2012||Aug. 21, 2012||6.97||5,890|
|2013||Sep. 11, 2013||7.80||2,000|
|2014||Aug. 26, 2014||9.82||7,910|
One method of analysis will be to graph flows based on the data in table 2.2 vs. time to extrapolate flows in 100, 500, and 1000 years. Once established these values will be compared to two other analysis methods.
Another method of analysis requires using a NOAA interactive map to generate point based data frequency estimates in tabular format. The frequency of events range from 1 to 1000 years with a precipitation duration ranging from five minutes to 60 days (table 3). This will give a baseline in determining the actual likelihood of past precipitation events form NOAA records (table 4). The rainfall/snowmelt events will be compared to stream flows. The result of this comparison is to label peak flows in Boulder creek with an event frequency. The timeframe is limited to 24 hrs. By the stream gauge data from tables 1 and 2. Graphical analysis should result in an accurate prediction of flows based on a storm event of 500 and 1000 year frequencies.
Surveying was conducted north of the Hillside Mine inside of Boulder Creek. There is only a 120 yard span of Boulder Creek that has the potential of compromising the mine cap’s integrity. The total station was setup along the thalweg of Boulder Creek just 45 feet north of the mine cap and towards the western part of the 120 yard span. The second total station setup was towards the eastern part, which allowed hidden sections of the creek to be captured. Survey data was collected throughout Boulder Creek, which included the banks, thalweg, and other critical points that can contribute to the development of the topographic map of the project site. Prisms and prism rods where used to collect the survey points. The survey points were stored into a data collector which connects to the total station and allows the input data to be matched between the two devices. The data was extracted from the data collector onto a PC where AutoCAD Civil 3D can process the data.
The surface created by the survey data is shown in the Appendix. With an area of 230,000 sq ft. and a length of approximately 700 yards along the thalweg, this surface shows the most critical section along the tailing pile. An elevation model of surface was also created as another visual where one can see the elevation difference as shown in the appendix. A profile drawing of the thalweg can be seen in the Appendix. The alignment shows that thethalweg has an approximate 1.5% slope. The three cross sections shown in the Appendix correspond to their labels. The cross sections represent upstream, center, and downstream. As seen in the drawings, the side slopes reach a vertical height of approximately 60 ft. from the stream bed. This is a good sign considering the stream channel needs to hold a 500 year flood event.
2.5 Task 5:HEC-RAS
The geometric data from AutoCAD as well as the flow data were inputted into the HEC-RAS program. Along with using the cross sections from our AutoCAD surface, and average slope and manning’s roughness coefficient were implemented. An average slope of 1.5% was used and a manning’s coefficient of 0.035. HEC-RAS used all the data provided and created the models, as seen in the Appendix. The main objective of these models are to make sure that the calculated flow does not exceed the cap boundary line. The 100-year flow of 24,000 cfs did not come close to the cap line with approximately 40 vertical feet to spare. The 500-year flow event as requested by the client resulted in a flow of 30,000 cfs. This flow did not cause any overtopping and had approximately 30 vertical feet to spare before hitting the cap line. Overtopping will not be an issue with any of these storm events.Each model can be seen in the Appendix. KASH Engineering has determined that the site is not in danger of overtopping. Although the storm events do not reach the cap line, the high amounts of energy of a stream flowing at this rate could cause undercutting and possible erosion issues.
Kash Engineering will work closely with the client and notify the client of progress throughout the span of the project. Kash Engineering will also communicate with the client to ensure the project tasks that have been stated are completed.
The project workload will be divided throughout the Kash Engineering staff. Based on personal qualifications, workload, and available time, individual tasks will be completed in the most efficient manner possible. The team will peer review all aspects of this project to ensure quality and consistency throughout the process.
The project schedule is displayed below in figure 3.1
Figure 3.1: Project Schedule
The project will begin on the Jan 19th and be completed by May 16th. These tasks are essential to the completion of the project but are not entirely dependent on each other. The red line indicates the critical path of the project.
This section includes an explanation of the positions required and the cost of service to complete the project
Surveyor: The project surveyor is responsible for recording exact measurements of Boulder Creek.
Project Engineer: The Project Engineer is responsible for reviewing all project work and will determine that all client requirements are met. The Engineer will maintain a safe working environment by enforcing proper procedures and regulations.
Hydrology Analyst: The Hydrology Analyst will perform all hydraulic and hydrologic modeling.
Project Manager: The project manager will oversee the project from beginning to the end. The project manager will ensure the project is moving along according to plan and all tasks are being completed.
Figure 4.1 shows the cost breakdown for the project. The estimated personnel costs for each position is shown along with number of hours per task each position will be working. Overhead is included in these billable rates. Additional expenses include travel costs and lodging. Figure 4.1 displays the cost analysis in detail.
Figure 4.1: Cost Breakdown for Project
In this study, we discussed about Hillside mine located in region of Arizona. The study emphasized on different reason for drought in this reasons regarding this mine. This was all about contaminants, such as metal and acids, which hindered human friendly weather. In this region, there was an issue, which had to be resolved. The objective has been justified with different results in lab. The two methods were prominent, as these were well enough to derive information through different graphs flows. In addition, in a lab, there was another method, named as NOAA, which has helped us to navigate data in form of frequency and in a tabular form. The potential damage has been observed through investigation in lab, as it is caused to contamination due to erosion of tailing.
Due to hydrology field of engineering, this was effective to derive results regarding clime damage. These results are mentioned as lack of rain and bad environment fro humans, which causes different diseases. The Francis creek and boulder are navigated in relation to the site, which has helped to derive the damaged area die to contamination. The use of different gauges in labs was helpful will let us to derive expected results from the surveys.
Use of Auto Cad drawing has helped to consider area of 230,000 sq ft. In this navigation, the three cross sections were mentioned and used to depict affected areas due to contamination. The steam bed consideration was good to derive information regarding almost 500-flood event. The ups stream, center and downstream have been navigated in this phase of examination in lab. In addition, the interaction with client was effective, as the client was involved in the project with lucrative communication. From start to end, the interaction with client by KASH Engineering has helped to complete the project on time with expected results, shown in appendix.
- D. D. Gillham, “Winter Preview: El NiÃ±o contributes to a tale of two seasons,” The Weather Network, Feb-2015.
- “USGS TNM 2.0 Viewer,” USGS TNM 2.0 Viewer.
- “What are Hydraflow Extensions?,” What are Hydraflow Extensions?, Mar-2015.
- D. Feldman, Hydrologic Modeling System: HEC-HMS: US Army Corps of Engineers, Institute for Water Resources, Hydrologic Engineering Center, 2001.
- G. W. Brunner, HEC-RAS River Analysis System: User’s Manual. US Army Corps of Engineers, Institute for Water Resources, Hydrologic Engineering Center, 2001.