Wetlands, Best Management Practices, and Riparian Zones

105 .E55 no.957 cop.2 cial Report 957 try 1996 1995 James A. Vomocil Water Quality Conference Wetlands, Best Management Practices, and Riparian Zones Oregon 4,401, Water 4wAileft Resources 44$ OREGON STATE UNIVERSITY EXTENSION SERVICE Research 0 Institute The Oregon State University James A. Vomocil Water Quality Conference The Oregon State University Extension Service and the Oregon Water Resources Research Institute cooperate to sponsor an annual conference on critical water-related issues facing the State. Since 1988, the James A. Vomocil Water Quality Conference has brought together interests and expertise related to specific water issues. The goal has been to speak in a language understandable to the entire community of individuals concerned about water. Jim Vomocil, for whom this conference is named, is a recently retired Extension specialist with a driving commitment to make water-related information accessible to the entire public impacted by water management decisions. The annual water quality conference was his creation to pursue that objective. The Conference is held each year in early November in Corvallis, Oregon. For information about future conferences, contact: Ron Miner Extension Water Quality Specialist Department of Bioresource Engineering Oregon State University Gilmore Hall, Rm. 116 Corvallis, OR 97331-3906 (541) 737-6295 Foreword 1 Treating Dairy Flush Water in a Constructed Wetland 2 Treatment of Pulp Mill Effluent with a Constructed Wetland 24 Best Management Practices for Peppermint Production 40 Water and Fertilizer Management in Potato Production 42 Epic Model Predictions of BMP Effects on Farm Runoff Quality 47 Reduced Nitrogen Fertilizer Applications for Increased Sugar Beet Production and Reduced Nitrate Leaching Losses 58 A Statistical Evaluation of the Water Quality Impacts of Best Management 71 The Potential of Off-Stream Livestock Watering to Reduce Water Quality Impacts 82 Furrow Mulching to Reduce Surface Water Pollution and Increase Profitability 93 Heat Source Version 1.0 94 Benefits and Costs of Riparian Habitat Improvement in the Tualatin River Basin 105 Relationship of Stream Water Quality to Land Use Patterns (BMPs) in an Agricultural Watershed: Tualatin Basin, Oregon 142 James A. Vomocil Conference 1995 Registration List 151 Foreword The Seventh Annual James A. Vomocil Water Quality Conference was planned after three topics had been selected as being of particular interest. Wetlands, Best Management Practices, and Riparian Zone Effectiveness were the topics. Speakers were invited who by virtue of their training, their experience, or their work assignment had insights worth sharing. This document is a collection of those presentations. In assembling the document, author submissions have been reproduced as submitted. You are invited to contact the presenters if you have particular questions. The wetlands section of the conference featured both the theoretical and the more practical aspects of both natural and constructed wetlands. Oregon's past has been described as an adventure in escaping wetlands. As a matter of fact, some claim the first industry of the Willamette Valley was the manufacture of clay tile to drain the swampy bottomland so people could begin to farm the area. Whether this is true or not, much of the natural wetland of the State has been destroyed in our taming of the landscape. It is common knowledge that wetlands were contributing to both the quantity and the quality of summertime stream flow. The speakers discussed our current state of knowledge and recounted their experiences with regard to wetlands. Best management practices (BMPs) are being prescribed for a variety of agricultural and forestry activities. These BMPs are based largely on our accumulated knowledge over the past 80 years. Only now are we gaining the specific data to establish the overall water quality impact of installing appropriate sets of BMPs on a watershed basis. One of the goals of this component of the program was to identify those areas in which we can specify BMP performance and those where we have little or no data to support their construction. Riparian zones are those lands along the stream bank that have immediate interaction with the water in the stream. As scientists and regulators become better informed about natural processes, it becomes increasingly apparent that stream quality is highly dependent upon the status of the riparian area. Vegetation growing in the riparian zone tends to filter out the bacteria and other particulates from runoff before it can enter a stream. That same vegetation uses nutrients that otherwise would enter the stream. Shade from streamside vegetation also tends to reduce the direct solar radiation striking the water, thereby reducing the maximum stream temperatures. The luncheon keynote speaker was Fred Otley, a fourth-generation rancher from Diamond, OR. Mr. Otley currently serves as president of the Oregon Cattlemen's Association and is active in a number of organizations devoted to improving the management of high desert and forested grazing lands. He uses his undergraduate training in rangeland resources and in agricultural and resource economics to cooperate with the scientific community and to work within the political process to improve watershed and environmental management. TREATING DAIRY FLUSH WATER IN A CONSTRUCTED WETLAND S.F. Niswander, J.A. Moore, M.J. Gamroth, and S.M. Skarda Dept. of Bioresource Engineering Oregon State University Corvallis, OR 97331-3906 ABSTRACT Six parallel wetland cells, each 5.5 m x 26.7 m, were constructed in western Oregon. These wetlands were constructed in 1992, and began receiving wastewater from a flush dairy operation in the fall of 1993. The six cells were planted with either Thypha latifolia or Scirpus acutus. The wetlands were all loaded at a hydraulic loading rate of 3.94 cm/day, which resulted in a 7.7 day retention time. The mass loading of biochemical oxygen demand and chemical oxygen demand averaged 193 and 588 kg/ha-day, respectively. Samples of the influent and effluent were collected from all wetland cells twice a month. The samples were analyzed for fourteen water quality parameters. Average removal rates for these parameters were: chemical oxygen demand 58%; biochemical oxygen demand 66%; total solids 52%; total suspended solids 67%; total phosphorus 63%; orthophosphorous 61%; total Kjeldahl nitrogen 55%; ammonia 55%; nitrate 72%; fecal coliforms 93%; and dissolved oxygen 96%. The inlet pH, conductivity, and temperature averaged 7.38, 1,405 umho/cm, and 9.9 °C, respectively. The outlet pH, conductivity, temperature averaged 6.75, 944 umho/cm, and 7.7 °C, respectively. The wetland cells appeared to be oxygen limited at this "high" loading rate. Higher percentage removal might be expected if the cells were supplemented with oxygen or loaded at a lower rate which does not deplete all of the oxygen. INTRODUCTION The use of constructed wetlands is a relatively new treatment technology with most of the research results coming from the treatment of domestic wastewater. Research results from early work in England and most recently the United States, indicate this new technology offers promise. In the last several years wetlands have been installed and are treating a wide variety of effluents, including wastewaters from pulp mills, sugar refineries, acid mine drainage, food processing, storm water runoff, and more recently livestock wastewaters. Last year, Purdue University sponsored a conference dedicated to "Constructed Wetlands for Animal Waste Management" (DuBowy and Reaves, 1994). There were 18 papers presented at this conference. Several of these reports discussed the research projects that are underway or currently under construction. There were very few mature systems reported on at this time and only recently have data from the treatment of livestock systems been seen in the literature. 2 Most of the recent work has been reported on free water surface system. Some of the earlier work looked at subsurface flow units. Research in Australia showed that effluent from an abattoir processing poultry and piggery effluent treated in a gravel based wetland system removed nutrients and suspended solids (Finalyson et al., 1990). The study also showed the addition of plants to the system improved the performance. In another study, dairy wastewater was routed into a large natural, 6.4 ha, wetland that removed over 99.9% of the biochemical oxygen demand (BOD) (Costello, 1989). A non-typical wetland treatment system using an aquaculture component with an integrated constructed wetland achieved 75% BOD removal when treating swine waste (Maddox and Kingsley, 1989). Agricultural wastewaters typically have a high BOD, which consumes most of the available oxygen. Wetlands treating agricultural wastewaters are therefore generally oxygen limited. Gray et al. (1990) reported insufficient oxygen transfer in reed bed systems treating agricultural effluents. This problem was partially solved by installing a down flow unit upstream of the wetland cell that transferred additional oxygen and allowed the system to handle effluents of up to 3000 mg/1 BOD. For the interested reader, more detailed information is available in two recent proceedings: "Constructed Wetlands for Water Quality Improvements," edited by G.A. Moshiri, 1993, and the "Proceedings of the 4th International Conference on Wetland Systems for Water Pollution Control," held in Guangzhou, China in November, 1994. Both proceedings report results from numerous

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