Gravel Mining part 2

Water quality criteria apply in relation to mining operations specifically to turbidity and temperature changes caused by their activities. Water quality criteria are guidelines only. They are not directly enforceable unless a violation can be traced to a point source discharge where limitations have been exceeded. Furthermore, all pollution generated by instream dredging operations is defined as non-point. Thus, turbidity or sedimentation originating from dredging does not fall under the jurisdiction of the Missouri Clean Water Law. Pollution caused by gravel washing is also often classified as non-point, especially where permanent settling basins are not constructed, therefore much of this activitv is also not regulated.

Regulation of gravel dredging also falls under Section 404 of the Federal Clean Water Act. A permit is required on any action that would result in "fill" in any waters or wetland in the United States. The U. S. Corps of Engineers administers this program. Interpretation of the law has been as varied as the activities this law regulates. "'Fill" has been interpreted in a number of ways. In the most conservative sense, it has been applied to any material stockpiled within the high water mark such as sand or gravel removed from the river. At the other and of the spectrum, any structure placed within the high water mark to remove such material (deadman or cable dredge, crane and bucket or even a bulldozer) has, at times, been designated as fill and necessitated a permit. The real regulatory power of this law is that before a Section 404 permit can be issued the projected action must be certified by the state as not causing a violation of the state's water quality criteria. The full ramification of the state's regulatory power under this law is not entirely known, but the law has been useful in controlling a number of other environmental alterations such as stream channelization and draining or filling of wetlands.

The full potential of Section 404 may never be realized because of recent efforts by the task force on regulatory relief. This committee has been reviewing a number of regulations in an effort to reduce the jurisdictional extent of the federal government.

This law has been identified as one area where regulations could be streamlined or eliminated altogether, although stiff opposition has been encountered from the U. S. Fish and Wildlife Service and other resource protection oriented groups.

In the early '80s studies on the effects of gravel mining were conducted on the Osage River and the Little Piney. The Osage study was initiated to determine the effects of commercial dredging on the pink pearly mussel, listed as endangered in the United States List of Endangered and Threatened Wildlife and the spectacle case, under review for inclusion in the list. A secondary objective was to gather similar data on other species of naiades (mussels).

The study area was located on the lower Osage River downstream from Bagnell.Dam on Lake of the Ozarks. The Osage originates at the confluence of the Marais des Cygnes and the Marmaton rivers and flows east about 250 miles to join the Missouri River. The Osage basin has a drainage area of over 16,000 square miles, making it the largest stream that flows entirely within the borders of the state. The lower Osage is low gradient, moderately clear, with long pools usually less than 10 feet in depth and has poorly defined riffles. Gravel and cobble are the principal bottom types with silt covering the riverbed in many of the deeper, sluggish pools.

Three large commercial sand and gravel operations, Ozark Sand Company, Osage Sand and Gravel Company and Roweth Sand and Gravel Company are located on the lower Osage River. Each operation is separated by 10 or more miles. Ozark Sand Company mines in the river with a crane dragline dredge and a crane with bucket.

Sand and gravel is processed with river water with a discharge through a settling pond back to the river. Osage Sand and Gravel Company hydraulically mines from the river with a cutterhead dredge mounted on floating pontoons. Roweth Sand and Gravel Company mines from the river with a dragline dredge. The latter two companies process the sand and gravel with river water and return it directly to the river without settling. The large excavation in the stream channel left by these mining operations may exceed 60 feet in depth.

Naiads were collected at 23 sites on the Osage River at 3-5 mile intervals. Physical and chemical site characteristics recorded included bottom type, water velocity, depth, temperature, turbidity, alkalinity, hardness, pH, and dissolved oxygen. Turbidity was monitored over a 3-4 day period. Water samples were taken each day before dredging and washing operations began and throughout the day at 2-hour intervals.

No living naiades were found in dredged areas of all three gravel operations. Some of the dredged areas sampled had not been worked for as long as 15 years. Few living naiades were found in the undredged river immediately adjacent to each operation. Well-developed naiad beds were found downstream, from gravel operations where the bottom substrate had not been disturbed.

The study showed turbidity was significantly higher during operation at Ozark Sand Company than before operation at stations 250 feet upstream and 250 feet, 800 feet, and 3,700 feet downstream No significant differences were found at stations 4,800 feet and 7,200 feet downstream. Turbidity was significantly greater in samples taken near the bottom than at the surface. Turbidity measurements taken at the other two commercial operations showed similar patterns; average turbidity was greater downstream during operation than before and decreased in a downstream direction. Turbidity also appeared to be slightly greater below the operations than above even after dredging had ceased because of the permanent disruption of the stream bottom.

Dredging activities may also indirectly impact naiades by altering fish populations. Since naiades must depend an fish as larval hosts and for dispersal, any activity that altered the species composition or movement of the fish population would also alter naiad distribution. Some host relationships are species specific and therefore directly affect their survival.

Marked effects on naiades were observed in dredged areas and areas immediately adjacent to the dredge site due to physical destruction of habitat. In addition to the physical destruction of habitat, other factors preventing re-colonization appeared to be the destabilization of bottom substrate and deepening of pools. The adverse effects of dredging on naiades are long lasting and re-establishment in dredged areas appears to take many years. Continued dredging within the existing operation zone at all three commercial sites would be unlikely to have additional serious impact on the population of the pink pearly mussel and the spectacle case. However, any expansion of dredging at existing sites or any new dredging should not be permitted without first conducting a survey to determine the presence of endangered species. The authors also stated that floodplain dredging at all sites would be unlikely to have adverse affects on the naiad fauna if the river con- figuration were not altered. Although turbidity was significantly increased downstream from dredging activities, the direct impact of turbidity could not be determined and additional research was recommended.

The study of the Little Piney River discusses the effects of ponding and subsequent thermal increases caused downstream from a gravel mining plant. The Little Piney River originates in the central Ozark region and flows about 35-miles north to its confluence with the Gasconade River. The basin drains approximately 250 square-miles, classifying it as a small to intermediate stream. The study area is located in the headwaters near the uppermost point of permanent spring-fed stream flow. The gradient is moderate and the water is normally clear, with long runs separated by well defined riffles and pools. Pools are generally less than 5 feet in depth. Clay and sand are the principal bottom types.

Havin Materials Company removes sand and gravel from a large floodplain excavation (20 acres) which has captured the adjacent stream channel. The lake subsequently formed on the Little Piney River is shallow, generally less than 10 feet in depth, and in contrast to the cool spring-fed stream, supports a warmwater fish fauna dominated by largemouth bass. The Missouri Department of Conservation maintains a trout management area beginning 1,000 feet below the Havin Lake. Catchable sized trout have been stocked on a put and take basis during the recreation season for a number of years. Natural trout reproduction does occur on a limited basis in this area.

The major source of flow in the study area, except during periods of precipitation, is from 7 surface springs, three above the gravel plant and four below. During low flow the uppermost three springs contribute 8 cfs of 57 F water which passes through the Havin Lake. An additional 16 cfs of spring water at the same temperature is added by the four springs downstream from the lake over the course of about 1 mile. Approximately 1/4 mile of stream on either side of the lake has been channelized by previous dredging. Consequently, all canopy vegetation has been removed and the stream is open to direct solar radiation.