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Federal Register 1 Vol. 45. No. 249 / Wednesday. December 24. 1980 I Rules and Regulations 85353 , smaller in size than sand. They are either unvegetated or vegetated only by algal mats. - (b) Possible loss 01 values: The discharge 01 dredged or fill material can cause changes in water circulation patterns which may pennanently flood or dewater the mud flat or disrupt periodic inundation. resulting in an increase in the fa te of erosion or accretion. Such changes can deplete or eliminate mud flat biota, foraging areas, and nursery areas. Changes in inundation patterns can affect the chemical and biological exchange and decomposition process occurring on the mud flat and chal!ge the deposition of suspended material affecting the productivity of the area. Changes may reduce the mud flat's capacity to dissipate storm surge runoff. ~ 230.43 Vegetated shallows. (a) Vegetated shallows are permanently inundated areas thai under normal circumstances support , communities of rooted aquatic vegetation. such as turtle grass and eelgrass in estuarine or marine systems as well as-a number of freshwater species in rivers and lakes. (b) Possible loss of values; The discharge of drpJged or fill material can smother vegetation and benthic organisms. It may also create unsuitable conditions for their continued vigor by: (1) changing water circulation patterns: (2) releasing nutrients that increase undesirable algal populations: (3) releasi:1g chemicals that adversely affect plants and animals: (4) increasing turbidity levels. thereby reducing light penetration and hence photosynthesis; and (5) changing the capacity 01 a vegetated shallow to stabilize bottom materials and decrease channel shoaling. The discharge of dredged or fill material may reduce the value of vegetated shallows as nesting. spawning. nursery. cover. and forage areas. as well as their value in protecting shorelines from erosion and wave actions. It may also encourage the growth of nuisance vegetation. ~ 230.44 Coral reefs. (a) Coral reefs consist of the skeletal drposit. usuatly of calcareous or silicaceous materials. produced by the vital acti\"ities of anthozoan polyps or other Invertebrate organisms present in growing portions of the reef. (bJ Possible loss of values: The disc.harge of dredged or fill material can adversely affect colonies of reef building organisms by burying them. by releasing contaminants such as hydrocarbons into the water column. by reducing light penetration through the water. and by increa"sing the level of suspended particulates. Coral organisms are extremely sensitive to even slight reductions in light penetration or increases in suspended particulates. These adverse effects ",:m cause a loss of productive colonies which in turn provide habitat for many species of highly specialized aquatic organisms. I 230.45 Riffle and pool complexes. (a) Steep gradient sections of streams are sometimes characterized by riffle and pool complexes. Such stream sections are recognizable by their hydraulic characteristics. The rapid movement of water over a coarse substrate in riffles results in a rough flow. a turbulent surface. and high dissolved oxygen levels in the water. Pools are deeper areas associated with riffles. Pools are characterized by a slower stream velocity. a steaming flow, a smooth surface, and a finer substrate. Rime and pool complexes are particularly valuable habitat for fish and wildlife. (b) Possible loss of values: Discharge of dredged or filLm..aterial can eliminate riffle and pool areas by displacement, hydrologic modification. or sedimentation. Activities which affect riffle and pool areas and especially riffle/pool ratios. may reduce the aeration and filtration capabilities at the discharge site and downstream. may reduce stream habitat diversity. and may retard repopulation of the disposal site and downstream waters through sedimentation and the creation of unsuitable habitat. The discharge of dredged or lill material which alters stream hydrology may cause scouring or sedimentation of riffles and pools. . Sedimentation induced through hydrological modification or as a direct result of the deposition of unconsolidated dredged or fill material may clog riffle and pool areas. destroy habitats. and create anaerobic conditions. Eliminating pools and meanders by the discharge of dredged or fill material can reduce water holding capacity of streams and cause rapid runoff from a watershed. Rapid runoff can deliver large quantities of flood water in a short time to downstream areas resulting in the destruction of natural habitat. high property loss, and the need for further hydraulic modifiea tion. Note.-Possible actions to minimize adverse impacts on site or material characteristics can be found in Subpart H. Subpart F-Potenltal Ellecls on Human Use Charactertstlcs Note.- The effects described in this subpart should be considered in making the factual determinations and the findiDlI of compliance or non-compliance in Subpart B. t 230.50 Municipal and prlval. wat.r supplies. (8) Municipal and private water supplies consist of surface water or ground water which is directed to the intake of a municipal or private water supply system. {b} Possible loss of ,'alues: Discharges can affect the quality of water supplies with respect to color. taste. odor. chemical content and suspended particulate concentration. in such a way as to reduce the fitness of the water for consumption. Water can be rendered unpalatable or unhealthy by the addition of suspended particulates. viruses and pathogenic organisms. and dissolved materials. The expense of removing such substances before the water is delivered for consumption can be high. Discharges may also affect the quantity of water available for . municipal and private water supplies. In addition. certain commonly used water treatment chemicals have the potential for combining with some suspended or dissolved substances from dredged or fill material to form other products that can have a toxic effect on consumers. I 230.51 Recreational and commercial fisheries. (a) Recreational and commercial fisheries consist of harvestable fish. crustaceans. shellfish. and other aquatic organisms used by man. (b) Possible loss of values: The discharge of dredged or fill materials can affect the suitability of recreational and commercial fishing grounds as habitat for populations of consumable aquatic organisms. Discharges can result in the chemical contamination of recreational or commercial fisheries. They may also interfere with the reproductive success of recreational and commercially important aquatic species through disruption of migration and spawning areas. The introduction of pollutants at critical times in their life cycle may directly reduce populations d commercially important aquatic organisms or indirectly reduce them by reducing organisms upon which they depend for food. Any of these impacts can be 01 short duration or prolonged. depending upon the physical and chemical impacts of the discharge and the biological availability of contaminants to aquatic organisms.