Beneficial Use Attainment
The Platte River, including all of its tributaries, is classified for aquatic use, livestock watering, and wildlife use. The Platte River, 102 River, and Little Platte River, including Smithville Lake are also classified for drinking water use and irrigation. Smithville Lake also has classifications for boating and whole body contact (MDNR 1986a). Minor elevations in fecal coliform bacteria levels in lake arms following runoff may occur in Smithville Lake (MDNR 1995). However, whole body contact recreation should remain unaffected.
Water quality that maintains diverse aquatic communities and acceptable fisheries uses throughout the basin should remain adequate, though biomass and biotic diversity may be limited in various streams within the basin due to high levels of non-point suspended solids, sedimentation, occasional low dissolved oxygen, increased nutrification, and in short reaches, by point source pollution. Water quality for livestock and wildlife watering should remain satisfactory within the basin. Water quality of drinking supply sources should also remain adequate. Manganese and iron may pose occasional taste, odor, and staining problems if not adequately removed by conventional water treatment or if water is drawn from deep strata of Smithville Lake. Taste and odor may also be a problem if algal growth is excessive (MDNR 1995).
Chemical Quality of Stream Flow
Suspended sediment, elevated water temperatures, and acidic inflows are water quality problems affecting streams within the Platte River basin, and all are negatively affected by weak base flows. High levels of suspended sediments in runoff are a significant contributor to the low aquatic diversity associated with basin streams. Basin streams often have manganese and fecal coliform levels that are commonly above Missouri water quality criteria (USDA-SCS 1982).Elevated water temperatures are harmful to fish survival and diversity. Water temperatures in excess of 90o F have been recorded in basin streams. These temperatures are found to be detrimental to the growth of largemouth bass, freshwater drum, bluegill, and crappie. Temperatures in excess of 80o F are found to be damaging to spawning and egg development of channel catfish, buffalo, and gizzard shad (USDA-SCS 1982). Due to the shallow nature and weak base flows in basin streams, water temperatures in excess of 80o F probably occur frequently during fish spawning and egg development (USDA-SCS 1982). Current trends show an increase in nitrate levels within basin streams, and this is thought to be associated with increased runoff of nitrogen-based fertilizers or increased runoff of animal waste (MDNR 1986b). Two years of water quality data from the gaging station at Sharps Station near Platte City are presented in Table Wq01.
Contaminants, Fish Kills, and Health Advisories
Since 1985, the Missouri Department of Health has issued a fish consumption advisory for Missouri, excluding the Ozarks (MDOH 1996). This advisory includes the Platte River basin. Consumption of fatty fishes such as catfish, common carp, suckers, freshwater drum, and paddlefish should be limited to no more than one pound per week (less than one pound per week for pregnant or nursing females and young children) due to higher levels of contaminants found in these types of fish. No consumption advisories apply for bass, sunfish, crappie or walleye (MDOH 1996). No fish consumption advisories are posted for the Iowa portion of the basin (R. Currier, Iowa Department of Health, personal communication).
Contaminant samples collected from Smithville Lake in 1994 showed that chlordane levels exceeded the National Academy of Science/National Academy of Engineering (NAS/NAE) 1973 chlordane guidelines for protection of wildlife (100 parts per billion, ppb), but fell below the Food and Drug Administration action level of 300 ppb. Only chlordane exceeded the NAS/NAE guidelines for protection of wildlife based on the 28 contaminants sampled (Buchanan 1994).
Numerous fish kills have occurred throughout the basin, and these have been attributed to naturally occurring conditions. Some of the larger fish kills have resulted from low dissolved oxygen levels associated with low flow conditions and increased water temperatures (Duchrow 1994). These conditions undoubtedly occur basin-wide. In addition, results may be magnified due to increased sedimentation and low base flows caused by channelization and detrimental agricultural practices (MDNR 1995).
Another threat to fish populations throughout the basin has been the improper management of municipal sewage and the subsequent runoff into receiving streams. Historically, this has been a chronic problem with the cities of Maryville and St. Joseph. Until 1971, the city of Maryville operated two primary sewage treatment plants, both located on tributaries to the 102 River. These facilities were responsible for several fish kills, the largest of which killed an estimated 250 fish and affected seven miles of the 102 River in 1971. In 1970, Maryville constructed five new sewage lagoons and shut down the existing plants. Pollution in the two tributaries and the 102 River ceased, and the present discharge has no apparent adverse effects on stream fauna. The eastern one-fourth of St. Joseph is drained by the Platte River basin, and at one time, 15 miles of small streams and 12 miles of the Platte and 102 rivers within this portion of the basin were considered to be grossly polluted from untreated municipal sewage runoff (MDC files). Although no documented fish kills were directly linked to sewage treatment plant (STP) discharges, the problems below the St. Joseph plants continued to be documented through 1981. Currently, the city of St. Joseph operates one STP within the Platte River basin, and no fish kills have been attributed to its effluent. A listing of municipal STP's and other permitted point pollution sources can be found in Tables Wq02 and Wq03.
Fish kills associated with runway de-icing using ethylene glycol and industrial effluent from Kansas City International Airport as well as municipal effluent from the Kansas City -Todd Creek STP have been a chronic problem in Todd Creek since 1976. This situation currently requires monitoring for metals and should be carefully reviewed for possible toxic effects (MDNR 1995). Enforcement actions may be forthcoming if violations continue (Duchrow 1994).
Another concern to fish populations within the Platte River basin is runoff of livestock manure, both from ranging animals and concentrated feedlot sources. Large documented fish kills have not been directly linked to livestock waste runoff in the basin. However, this is a concern due to recent fish kills in northwest Missouri caused by livestock manure spills from concentrated animal feeding operations (CAFO's) in other river basins.
Norris and Sons Trash Service and the city of St. Joseph operate landfills near Pigeon Hill Conservation Area in Buchanan County. Leachate from these landfills has been responsible for past fish kills, and has been a noted contributor of pollutants to Pigeon Creek. The original landfill was constructed directly over a tributary to Pigeon Creek, and was responsible for most of the problems. Today both landfills are under state regulations, and safe operating guidelines have been put into place that should alleviate further problems. Four companies (Amoco, Mapco, Platte Crude, and Williams Brothers) maintain oil pipelines that underlie streams within the basin. These pipelines present a potential hazard for aquatic populations should a break occur.
A. Municipal- Within the Missouri portion of the Platte River basin there are four surface water intakes designated for municipal use (Figure Wq01). Two surface water intakes are located on Smithville Lake and serve the cities of Smithville and Plattsburg. One is located on Mozingo Lake and serves the city of Maryville. The other municipal surface water intake within the Missouri portion of the basin draws directly from the 102 River and serves the city of Maryville (MDNR 1996).
The Iowa portion of the Platte River basin contains three surface water intakes for municipal use (Figure Wq01). Two of the surface water intakes are located on reservoirs and serve the cities of Lennox and Bedford. The other surface water intake is located on the 102 River at Bedford and serves as a backup system. (J. Riessen, IADNR, personal communication).
B. Agricultural- Water use for irrigation purposes in the Missouri portion of the basin is minimal, although it varies annually depending upon rainfall. Only two of the nine Missouri counties within the basin (Andrew and Platte) reported any water use for irrigation (range 0.1 to 99 million gallons) during 1984 (MDNR 1986a).
Municipal sewage treatment plants are the major point-source pollution concern within the basin (Table Wq02; Figure Wq02). Surveys directly below basin STP's have noted changes in fish and invertebrate quantity and quality, increased turbidity, and lowered beneficial use potentials. Improperly treated waste water has the potential to add excessive nutrients, elevate ammonia levels, increase levels of fecal coliform bacteria, and cause low levels of dissolved oxygen in receiving streams. Approximately 10 miles of stream (near the metropolitan areas of St. Joseph and Maryville) in the basin are thought to be negatively impacted by sewage effluent. These discharges have been responsible for severe stream degradation in the past. Currently STP's are monitored regularly and come under the scrutiny of National Pollution Discharge Elimination System (NPDES) permits. Non-municipal sewage effluent does not have large negative impacts on basin streams (MDNR 1995).
Unauthorized discharge from lagoons or pits serving CAFO's is another potential point-source pollutant within the basin. These discharges have been responsible for extensive fish kills in north Missouri, although no spills of this type have been documented as causing fish kills in the Platte River basin. Currently there are 75 CAFO's permitted within the basin, and it has been estimated that they generate 3,013,047 PE (human population equivalent) of waste annually (MDNR 1996 data). A listing of active and proposed CAFO's within the entire basin can be found in Table Wq04.
Non-Point Source Pollution
Non-point source pollution has the greatest negative influence upon water quality within the Platte River basin. The most common problems associated with non-point sources are low dissolved oxygen, high levels of turbidity, and organic nutrients, all of which are influenced by excessive runoff and extended low flows. The major factors contributing to non-point source pollution include channelization, intensive row cropping, and livestock (MDNR 1995). Urban construction and runoff may negatively affect basin streams in the Kansas City and St. Joseph areas (MDNR 1995).
Land use within the basin is dominated by row cropping and grazing of pasture land. One effect of intensive row cropping is increased runoff. This leads to increases in both upland and stream bank erosion and delivers high sediment loads and agricultural chemicals directly to basin streams. It is estimated that 23 tons of soil per acre are lost annually using straight row cropping with conventional tillage. Soil losses due to sheet and rill erosion on untilled uplands is 11 tons per acre annually. Gully erosion occurs at a rate of 1.2 tons per acre annually. This rapid erosion results in increased turbidity, degraded aquatic habitat, and increased nutrient and pesticide loads into streams (MDNR 1995). The Conservation Reserve Program (CRP) has removed some of the highly erodible land from production, but most of these CRP contracts will expire by 1998. Under the 1996 farm bill it has been estimated that erosion rates in northwest Missouri may rise from 10 to 40 percent as these highly erodible lands return to production (Otte 1996).
Livestock continues to be the main non-point source of organic nutrients to basin streams (MDNR 1995). The total number of livestock within the basin is estimated to equal 4,017,858 PE (T. Barney, USDA-NRCS, personal communication). The extent to which water quality, and subsequently aquatic life, is negatively affected by animal waste is difficult to estimate. The lack of adequate vegetation or buffer strips between feedlots or holding facilities and the stream allows runoff to carry waste and soil directly to streams. Direct access to streams by cattle is another major non-point pollution source within the basin. Excessive or untimely land application of animal waste can also add pollutants to basin streams. All of these situations can result in increases in sedimentation, fecal coliform bacteria, phosphorus, nitrates, ammonia nitrogen, and lowered dissolved oxygen (MDNR 1989).