Rathbun Lake Monthly Water Quality Monitoring near Honey Creek Resort Park (HCRP) Pre-Construction Phase April 2006 Event 1 Donna S. Lutz Water Quality Specialist Assistant Scientist Department of Civil, Construction and Environmental Engineering Iowa State University Project Introduction Water quality monitoring of Rathbun Reservoir in the vicinity of the planned Honey Creek Resort Park (HCRP) is being undertaken to gauge whether construction activities are having an adverse affect on lake water quality and, if necessary, adapt management of stormwater. HCRP is being planned by TSP architectural firm (http://www.teamtsp.com/) with final resort management by Regency Hotel Management (http://www.regency- mgmt.com/index.php). Background Information Rathbun Reservoir is located on the Chariton River in Appanoose County, Iowa. The reservoir began operation in 1969 and is managed by the Kansas City Corps of Engineers District. The reservoir’s authorized purposes include: flood damage reduction, recreation, fish and wildlife, water quality, water supply and navigation (See Appendix A for reservoir and dam data). Rathbun supplies water to Rathbun Regional Water Association, one of the largest rural water districts in the nation. The normal conservation pool is 904 feet NGVD (National Geodetic Vertical Datum) with a full flood pool elevation at 926 feet NGVD. The historical maximum pool was 927.17 feet NVGD on July 28, 1993 and the minimum pool was 898.38 feet NVGD on January 26, 1995 (see Appendix B). Major inflows into the reservoir include the Chariton River (USGS 06903400) with a long-term average flow of 119 ft/m3 and the South Fork Chariton River (USGS 06903700) with a long-term average flow of 122 ft/m3 (see Appendix C for USGS station records). The long-term average annual precipitation at Rathbun is 36.31 in., ranging from a minimum of 18.06 in. in 1988 to 56.86 in. in 1982 (see Appendix D). Long-term precipitation records at Albia, Centerville and Chariton are listed in Appendix E. Iowa DNR licenses land from the Corps for wildlife management. The IDNR also operates the Rathbun Fish Hatchery and a fisheries research facility, located below the dam. Now, the IDNR is developing the Honey Creek Destination State Park, which will be Iowa's first State Park to offer a full range of overnight accommodations and a broader range of outdoor recreational activities for the whole family. The planned facility development includes a 108-room lodge, conference center, indoor aquatic center, 18-hole golf course and over 30 family and group cabins. In addition, the normal array of state park facilities will be provided: Semi-enclosed picnic shelters, paved multi-purpose trails, hiking/nature trails, boat ramp, boat-docking facilities, and an upscale RV campground. These facilities will be located on an 850-acre tract of land on the north shore of Rathbun Lake. The existing Honey Creek State Park (an additional 850 acres) lies across the bay, and development plans include a pedestrian trail bridge to link the two parcels. IDNR’s original site plan is attached as Appendix F). There are 10 ecoregions and subecoregions within the state of Iowa (IDNR http://wqm.igsb.uiowa.edu/wqa/ecoregions.html ). Rathbun Reservoir is located in the Loess Flats and Till Plains ecoregion (#40) which is characterized by: Deep to moderate loess deposits over glacial till and dark, shallow soils are characteristic of the Loess Flats and Till Plains ecoregion. Loess deposits generally increase to the south, especially near the Missouri River. Several streams have headwaters in this region, and the topography varies from flat to moderately hilly. Valley sides are not steep, with slopes generally less than 10%. The Chariton River area is a more dissected and hilly area within this region. It lacks glacial till in many places and has a greater drainage density and more woody vegetation in stream reaches than in other parts of the ecoregion. Natural wetlands occur along the Grand River and several other rivers in the region. Soils are inherently fertile, but use can be limited due to severe erosion. Land use includes areas of cropland, pasture in the valleys and on upland slopes, and bands of woodland. Corn and soybeans are the major crops. Other entities are conducting water quality investigations in the area and an effort will be made to share information. The Rathbun Land and Water Alliance in cooperation with the Iowa Department of Natural Resources, Iowa State University (Ecology, Evolution and Organismal Biology Department’s Limnology Lab), and US Army Corps of Engineers conducts water quality monitoring for pesticides, nutrients, bacteria, and sediment in Rathbun Lake and the lake's tributaries. The monitoring program provides the Alliance and its partners an understanding of water quality conditions in Rathbun Lake and watershed to support decision-making regarding the protection and management of the lake for its multiple uses which include drinking water supply, recreation, fish and wildlife habitat, flood damage reduction, downstream water quality improvement, and storage for supplementing navigational flows. The monitoring program consists of monthly and event sample collection and analysis from 15 tributary sites in the watershed, four sites in the lake, and one site at the lake outlet in the Chariton River. Monitoring results indicate that continued high sediment, nutrient, and pesticide loading in Rathbun Lake and its tributaries poses a serious threat to the water supply, recreational, and habitat uses of these water bodies. http://www.rlwa.org/3_waterqualitymonitoringprogram.html Rathbun Lake Monitoring for HCRP April 2006 – Event 1 Introduction Water samples were collected for the first time on April 18, 2006, at several sites on Rathbun Lake to monitor base-line conditions before construction begins at the Honey Creek Resort Park (HCRP). Samples were collected at three locations as shown on the following map. Sites RL-1 and RL-2 are located approximately 75 feet from the lakeshore on either side of the peninsula where the HCRP lodge will be located. Site RL-1 is located in an unnamed creek embayment just to the west of the resort area. Site RL-2 is located in the Honey Creek embayment just east of the resort area. Site RL-3 is located in the main lake down-lake from the other two sites. Monthly monitoring at these locations is intended to alert developers, in a timely manner, to any contamination of the lake that may be due to construction activities. This monitoring is supplemental to stormwater pollution abatement and monitoring activities that are also being undertaken. Construction Activities in Progress Pre-construction phase, the only activity has been surveying. Hydrology, Climatology and Sampling Conditions On April 18 the lake level was 901.77 feet NGVD (COE internet). The inflow from the Chariton River as measured near Chariton, Iowa (USGS gage 06903400) was 1 ft3/s and the peak flow over the last month was 27 ft3/s on April 1. The inflow from the South Fork Chariton River as measured near Promise City, Iowa (USGS gage 06903700) was 6 ft3/s and the peak flow over the last month was 77 ft3/s on April 1. The outflow from Rathbun Reservoir (USGS gage 06903900) was 20 ft3/s, ranging from 3 ft3/s to 200 ft3/s over the last month. See accompanying discharge graphs. Recent weather has been warmer and drier than usual. Precipitation at Rathbun Dam (NWS-COOP Station RAD14) over the previous 72 hours in 24 hour increments was 0.01 inch, 0.46 inch and 0.00 inch and precipitation over the last month was 2.84 inches. The latest significant rain event (>0.5 inch) occurred on April 2 (0.61 in). See accompanying precipitation data table. Weather conditions during sample collection were partly cloudy and breezy with temperatures in the mid-70s (oF). Boating pressure in the area is measured by the number of boat trailers in the existing Honey Creek ramp area. Upon arrival on April 18 there were 12 boat trailers. Field Results Water samples were collected between 1115 and 1310 CDT. Field tests were conducted at the site or within 24 hours of collection. Lake water appeared greenish-yellow with Secchi disc depths of approximately 0.7 m. The water depths at Sites RL-1, RL-2 and RL-3 were 6 meters (m), 4.5 m and 8.75 m, respectively. Discrete depth samples were collected at two depths (0.25 m under the surface and 1m from the bottom) for water temperature, pH, dissolved oxygen, total alkalinity, total hardness, turbidity and specific conductance. Results from the above parameters were similar with depth at each site and between sites indicating the reservoir was well mixed. The only discernible differences between sites were noted in pH and turbidity, with slightly lower pH at Site RL-3 (main lake) and slightly greater turbidity at RL-1 (east embayment). Dissolved oxygen concentrations were similar, as noted above, and ranged between 9.5 mg/l (ppm) and 10.0 mg/l (95% to 99% saturation). All results from field analyses are listed in accompanying data tables. Lab Results The Environmental Engineering Research Laboratory, part of Iowa State University’s Department of Civil, Construction and Environmental Engineering, conducted all remaining chemical and biological analyses. All results are listed in accompanying data tables. A six-foot PVC sampler was used to obtain integrated depth samples for solids and nutrient samples. Samples for all other parameters (bacteria, metals, organics and pesticides) required direct collection into sample bottles and thus were collected from just under the water surface. Integrated water column samples Solids- A suite of solids parameters was analyzed. Solids results were similar at all sites, with total solids ranging from 193 mg/l (RL-1) to 184 mg/l (RL-2).