Requested by Jeffrey Sanchez. February 21, 2007

Transcription

1 Application to Conduct research on the Butte Creek Ecological Reserve Requested by Jeffrey Sanchez February 21, 2007 Understanding the exchange between ground and surface waters is essential to many aspects of the Environmental Sciences. It is crucial to developing water budgets and has implications for aquifer recharge, aquatic habitat quality and riparian zone hydrology. By addressing certain aspects of this exchange, the processes can be simplified to the point that accurate quantitative assessments can be made. Due to the nature of subsurface exchanges, direct flux measurements are difficult to make. By using heat as a tracer, the monitoring the movement of water in the riparian zone can be made manageable. The interaction of ground water and surface water can be traced and analyzed by monitoring the temperatures of both the stream and the ground water. USGS Publications C-1260, and WRIR as well as work by Anderson (2004) establish methods of measuring ground water temperature beneath streams and using temperature gradients to determine if the reach is gaining or losing water to the ground. These published works rely on ground water temperature measurement from directly beneath the stream bed to determine the direction of flow. While it is important to understand the hydrology beneath a stream, it is not always feasible to place instruments directly into the stream bed. By constructing an array of piezometers fitted with temperature sensors, I will modify the under-stream sampling method by measuring groundwater temperature adjacent to the stream. By sampling outside of the stream bed, critical aquatic habitat can be protected. The piezometers will provide water level measurements, and coupled with appropriate equations, I will develop a model to use near-stream ground water temperatures to determine groundwater- surface water interactions. The site I will instrument is located in the Butte Creek Ecological Reserve (BCER), located on Honey Run Road in Butte County. The field site is located approximately 300 meters east of the storage shed on the BCER. Figure 1 shows an aerial view of the Reserve with pointers to the proposed site. At flows of 3,500 ft³/s the site is approximately 1-2 feet above the water line. When choosing locations for piezometers, natural vegetation will be avoided to minimize impact to the Reserve. The installation of the piezometers will include probing for and removing large cobbles in the first foot of each hole. A pipe will then be driven into the ground using a slide hammer. If the pipe is stopped by large cobbles, the pipe will be removed and another attempt to drive it in will be made nearby. Once the pipes are in place the tops will be painted silver to reduce solar heating, and caps will be fitted to prevent tampering or removal of the temperature sensor inside. At the edge of the creek three simple stage gauges will be inserted into the stream bed. These gauges will consist of a six-foot garden stake driven two feet into the stream bed, with a PVC pipe attached by zip tie and marked with lines to measure water level. These will be inserted when water levels allow for safe installation. A cinder block with a temperature sensing data logger attached will be placed on the stream bed and will be

2 read only when the storage capacity of the unit is reached (not very often). During a period of low flows in the summer of 2007, the channel and field site will be surveyed and discharge measurements will be made. A 3 x 2 x 2 wooden foot locker will be chained to a tree in a discrete location to provide a secure storage for the main data logger and power supply. In late August or early September, all pipes, wires and staff gauges will be removed and recycled. Every attempt will be made to return the site to preproject conditions: e.g. filling in holes or depressions left from the pipe removal. The proposed site has undergone significant morphological and hydrological adjustments resulting from decades of gravel dredging in the main channel. The current near-surface geology is now dominated by deep cobble-boulder tailings piles. These porous deposits will allow ground water to fluctuate over short time periods and should show a gradient near the Butte Creek channel. By monitoring both the water level and temperature at nine locations near the stream bank, I will be able to detect any gradient present in three dimensions. Coupled with in-stream temperature and level measurements, I will be able to determine if the stream is gaining or losing over this reach. The broader implications of the results are yet to be determined. The array of instruments consist of three transects perpendicular to the channel, with three, six-foot deep piezometers each. Figure 2 shows the site and approximate locations of the main data logger and two transects. A central data logger (chained to local tree for security) will record the temperature of the groundwater from each hole. Powered by a 12-volt car battery, the central data logger unit will be connected to thermocouple wire which will spread out to each pipe in the array. By necessity, each wire must have the same length regardless of its distance from the central unit. One submersible HOBO data logger will be placed at the bottom of the channel to record ambient stream temperature, and one will be placed within the array to record air temperature. Roughly twice each week, the water level in the pipes will be measured using a sounding reel. Rough staff gauges (PVC pipe and garden stakes) at the edge of the channel adjacent to each transect will be used to measure stream level. By accurately surveying the site, I will be able to create a model of the area and plot the hydraulic gradient as well as the temperature gradient between the stream and ground waters. If the data produce results similar to those derived from beneath stream measurements it would validate the technique as well as provide valuable information about the hydrology of Butte Creek. Under the supervision of Dr. Karin Hoover, I will conduct the necessary literary and physical research to produce a high quality Masters Thesis. Dr. David Brown has agreed to be on my thesis committee and I am actively seeking a third member to assist with technical advising. I will seek the physical assistance of fellow undergraduate and graduate students in implementing the project and will repay them by increasing their understanding of fluvial and hydrological processes. Table 1 is a list of the equipment which I believe will be necessary to properly conduct this experiment. I have submitted a request for funding assistance to the Department of Geosciences, but due to budget limitations I do not expect the full cost will be covered. If there are any funding sources which I might utilize, please consider me for those or direct me to where I may apply.

3 Thank you for your time and consideration. Jeffrey Sanchez Approved by: Dr. Karin Hoover Department of Geosciences California State University, Chico

4 Figure 1. Shows approximate location of 3 transects, and main datalogger location. White line leads to parking area. Figure 2. Shows field site with 3500 cfs in channel. Locations of Transects will avoid vegetation.

5 Table 1. Equipment List (prices do not include taxes or shipping) 21x Multilogger*- Repair ($200 estimated) and Calibration ($200) by Manufacturer Cambell Scientific $400 Thermocouple Extension Wire 1000ft spool $260/ spool $260 Deep Cycle Marine Battery to power 21x Micrologger Batteries Plus (Chico) $80/ each $160 Hobo Brand Temperature Data Logger $49/ each Online order from $98 Galvanized Pipe for Piezometers Lowe s $9.83/ each $98.30 Miscellaneous Pipe Fittings- Joints $0.84, Caps $0.96, Risers $1.98, Driving pipe $5.43: Lowe s $43.23 Miscellaneous Equipment: ½ x 10 ft PVC pipe $1.08, Heavy Duty Fence Post 3.97, ¼ x 7ft chain $1.66/ ft, Bulk Zip Ties $6.98, Lowe s $31.59 Transportation Costs (gas money) 20 miles round trip (From CSUC) 2 times per week for ~20 weeks =800 miles; 800 $0.485/ mi = $388 Total estimated Transportation (Request for half that cost) $194 Total Estimated cost of Project $ * 21x Multilogger will be borrowed from Dr. Randy Senock*