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Ashland NFWCO
 Midwest Region
 MTAN Logo Dedicated To The Tribal Aquaculture Program Image of fish jumping.
        September 2005-Volume 53
 http://www.fws.gov/midwest/ashland/mtanhome.html **Coordinator:
          Frank G. Stone 
          (715-682-6185) Ext.
          202
          U.S. Fish and
          Wildlife Service
          Email: [email protected]**
          
          **Edited
              By:
              Elizabeth W. Greiff 
              (715-349-2195) Ext. 5141
              St. Croix Tribal Nat. Res. Depart.
            Email: ****[email protected]******
 Topics
  Of Interest: *           Repairing 
      Fish Pond Levees
    *           Renovating Leaky 
      Ponds
    *
      New Innovative 
        Aerator System
    *           Reference Material from the American Fisheries Society   The following submissions are the second 
      of a two part series regarding pond construction and repair. This 
      information was received from the Southern Regional Aquaculture Center and 
      has been edited. Repairing Fish Pond Levees
  By: Jim Steeby, Nathan Stone, H. Killian and Dennis Careman Many fish farms have older ponds that need repair. Pond renovation is 
  expensive, with costs ranging from $300 to 1,000 per acre, equal to one-third or 
  more of the initial earth moving cost of pond construction. Ponds are rebuilt 
  for two major reasons: To repair levees that have become so thin that maintenance and feeding 
  equipment cannot pass
  To dry pond bottoms to make harvesting more efficient. Soft, flocculent 
  (fluffy) sediments accumulate at the bottom of older ponds and impair seining. 
  The sediments are mostly silt and clay eroded from pond levees. Soil type, wind speed, pond size and orientation influence the rate of 
  erosion. Farmers have little control over these factors once ponds are built. To 
  extend the useful life of a pond, farmers must rebuild the levees properly and 
  take measures to reduce erosion by establishing vegetation as quickly as 
  possible after construction. Building Strong Levees The goal in rebuilding (or building) levees is to make them strong and as 
  erosion resistant as possible, given the engineering properties of the existing 
  soils. The useful life of a pond depends on levee design and construction 
  practices. Three design features are most important in increasing pond life: Flattening the inside slope of the pond levee
  Widening the top of the pond levee
  Strengthening the levee by compaction
  
  A gentle slope is critical to 
    dissipating
    wave energy before it reaches the bank Waves damage levees by undercutting the bank and leaving a vertical face on 
  the levee. When all the wave energy is directed onto the levee, the soil erodes 
  rapidly as bank sections slough off into the pond. Increasing the slope of pond 
  levees from 4:1 to 5:1 or 6:1 slows pond erosion on most clay soils. However, 
  for a 6:1 slope, you need to weigh the increased costs against the reduction in 
  levee erosion. For a 10-acre pond with a 6-foot-high levee, building the pond 
  with 6:1 inside slope costs about $3,000 more than one with a 4:1 inside slope. 
  There is more shallow water in ponds with flatter levee slopes, which increases 
  the habitat for marginal aquatic weeds. The wider top lengthens the useful life 
  of a pond by providing more levee area to erode before it becomes too narrow to 
  permit traffic. Strengthening The Soil Two primary factors determine a Soils strength in a given levee: Force and degree of compaction
  Soil moisture at the time of compaction Soil strength greatly affects how much a completed levee can resist erosion. 
  Draglines or trackhoes that simply dump pond sediments in piles and tamp the top 
  of the piles with the back of the bucket do not adequately compact the soil. The 
  compactive force is too small, and the soil is usually too moist for good 
  compression. In highway, dam and building construction, engineers test the soil 
  before and during construction. In practice, experienced contractors can 
  determine if the soil is acceptably moist by its behavior during construction. 
  Soil should be moist enough that equipment does not stir up clouds of dust. On 
  the other hand, it should not be so wet that tires leave ruts deeper than an 
  inch or two in the compacted fill. A sheepsfoot roller is often used to compact soils. It consists of a cylinder 
  with protruding blunt spikes, designed so that when it has made enough passes to 
  compact the soil adequately, the cylinder no longer touches the ground, but is 
  supported on the protruding feet. Repeatedly passing equipment over the soil 
  increases density, although each pass has less and less of an effect. Dirt pans 
  compact more than dozers, as the wide tracks on dozers are designed to float on 
  top of the soil. If you build a levee with a dozer, also use a sheepsfoot roller 
  to compact the soil. For proper compaction, route equipment uniformly over the 
  fill area during construction. Rain can interfere with levee repair. Compared to a sheepsfoot roller, 
  rubber-tired equipment leaves a smoother surface that allows rainwater to run 
  off. Compact levees on a slight sideways slope to help them shed water during 
  construction. To make the levee as strong and uniformly compacted as possible, 
  it is critical to place the soil in 6-inch-thick layers and compact each layer 
  before adding the next layer. Running equipment over thicker layers compacts 
  only the surface layer, leaving un-compacted soil underneath that is weak and 
  easily eroded. Mechanical Or Structural Treatments Several mechanical or structural treatments also protect pond levees 
  effectively, including rock riprap, geotextile fabric and soilcement. 
  Unfortunately, such methods are prohibitively expensive, except perhaps for spot 
  treatments. A 3-foot-high band (1 feet above and below the waterline) of 4 to 5 
  inch diameter rock riprap will greatly enhance the life span of the levee. 
  Adding a geotextile base where the rock riprap is placed slows erosion 
  significantly, but raises the total cost. Geotextile material used alone has 
  been successful on the face of levees. The fabric should extend 1 feet above 
  and below the pond waterline. Properly installed geotextile fabric should extend 
  the life of a levee by about 5 years. Soil-cement is a mixture of site soil and cement to resist erosion. The 
  cement is usually mixed at about 10 to 13 percent by dry weight with slightly 
  plastic clays or silts. The soil-cement mixture is placed in a 6-inch layer and 
  extends 1 feet above and below the normal water line. Correctly installed 
  soil-cement barriers control erosion for a long time. Vegetation Vegetation can stabilize stream, river and lake shores. Mulching reworked 
  pond levees (about 100 pounds of straw per 1,000 square feet) works well and 
  planting with rye grass, centipede grass or Bermuda grass as soon as possible to 
  reestablish vegetative cover will help reduce erosion. Contact your county 
  Cooperative Extension Service office for information on cover grasses best 
  suited to your location. Levee-stabilizing vegetation must not interfere with 
  harvesting. Any vegetation that reduces or impedes seining efficiency is 
  unacceptable. Rebuilding Ponds Draglines can reach into the pond and result in less severe trenching at the 
  levee base. This method may give relief from the worn levee for an additional 2 
  to 4 years. The best time to rebuild is during drier periods, which allow the 
  sediment to dry and grass to become established before rains wash soil back into 
  the pond. Late spring or early summer is best. For ponds older than 10 years, 
  draining and drying may be more suitable. A traditional way to rebuild levees is to drain the pond and wait for the 
  pond bottom to dry enough to support the weight of a tractor and dirt pan. 
  Typically, pond bottom soils crust over, forming a firm surface layer with moist 
  soils below. Disking the surface exposes deeper soils and speeds drying. A 
  bulldozer can break up and mound the bottom soils so that they dry faster. When 
  weather permits, use dirt pans to rebuild levees, such as in the initial 
  construction period. The principal advantage is that by this time soils have 
  dried enough to compact well during rebuilding. Breaking the sediment crust the 
  first time through the pond is essential for good drying. Alternatively, after the pond bottom dries enough to support a wide-track 
  dozer, use the dozer to push moist pond bottom soil to the levees. The dozer 
  rolls up on the levee to pack the material back in place. Then use tractor drawn 
  dirt pans to finish the pond to grade, leaving a smooth surface that slopes to 
  the drain. Bulldozers and dirt pans can be used to rebuild ponds as small as  
  acre. For best results, compact the soils in shallow layers using a sheepsfoot 
  roller or wheeled equipment. This method is usually reserved for ponds with deep 
  sediments (more than 2 feet deep) in ponds not drained in 10 to 15 years. After 
  all the water is gone, the dragline digs a 3 to 4 foot-deep drainout ditch along 
  the levee base around the entire pond, which allows water to weep from the pond 
  sediments and leave at the drain. Slope the drainout ditch to the drain to carry out unwanted water. When the 
  sediments have set up to a soft consistency (usually a week if no rain falls), 
  fill back in a section of the ditch at the shallow end of the pond to form a 
  ramp to allow a size 65D bulldozer to cross into the soft sediments. The 
  bulldozer makes passes down the pond length, rowing up the soft sediment on 
  either side of the blade on each pass. The sediment should be soft enough to still flow slightly. If allowed to dry 
  too much, the mud pushes down the pond rather than flowing to the sides. The 
  goal is to row up the mud (pile the bottom sediments in rows) down the pond 
  length for good drainage and quick drying. You may need to make more than one 
  pass, several days apart, to complete this stage of the process. The rows will 
  be 4 to 5 feet high and of equal width, with the parent soil showing slightly 
  between the rows. Rains will drain off the rows and flow down the channels left 
  by the bulldozer. Allow the rows to dry for 2 to 3 weeks, depending on rainfall, or until the 
  rows are a heavy plastic consistency. Then, bulldoze across the rows starting at 
  the pond center, moving toward the nearer levee. The push should pack the entire 
  distance to the levee. When all the sediment has been packed back into the levee 
  slopes, top a small amount of the original clay from the pond bottom back over 
  the packed sediment material. This minimizes erosion during the early period 
  when the pond is refilled. Expect the levee to settle some as the packed material compacts in the next 
  few months. With this method, a pond drained in late spring or early summer can 
  be back in use by midsummer in most years. Again, compaction is less than 
  optimum using this method. Rainfall determines the time needed to finish any process, but the initial 
  trenching and rowing process of this method allows rainfall to exit the pond 
  rather than soak into the sediments. Ponds rebuilt this way should last 10 
  years.  Renovating Leaky Ponds
  By:  Nathan Stone Prevention Proper site selection and pond construction methods will help prevent pond 
  leakage. Landowners should consult with the National Resources and Conservation 
  Service (NRCS) before building a pond. The Service has soil surveys with 
  valuable information on soil properties and their suitability for water 
  management. Taking core samples from a proposed pond site will help identify 
  areas of high permeability and prevent future problems. Cutting too 
      deeply during construction
      is a common cause of leaky ponds As adequate compaction and suitable moisture content are critical, a pond 
  basin should be in the middle layer of a soil profile. This middle layer is 
  called the B horizon and typically has the maximum accumulation of clay. The 
  parent material underneath the B horizon may have little clay. Finally, pond maintenance is important in preventing leaks from developing. 
  Levees should be mowed to prevent tree growth and to discourage burrowing 
  animals. Trees growing on levees are a frequent cause of leaks in older ponds. 
  However, once trees with substantial root systems become established it is 
  better not to cut them down, as leaks typically develop where dead roots decay. Identify the Problem In some cases the cause of a seepage problem may be apparent; in other cases, 
  the cause may be unknown. When there is excessive seepage, the first step is to 
  carefully examine the pond dam or levees. Seeps, wet spots or wetland vegetation 
  on or below the dam are indicators of leakage through or under the dam or 
  levees. Water also can leak through muskrat or crawfish burrows or through 
  channels left by rotten tree roots. Older ponds can develop leaks around drain 
  or overflow pipes. If the water drops rapidly, carefully check the perimeter of 
  the pond at the waterline for holes. In addition to inspecting the pond, gather as much information as possible 
  about the pond history, site characteristics, and construction practices used. 
  Important questions include: Was the site properly prepared by removing the existing vegetation and 
  topsoil
  Was the pond levee built properly, in compacted layers of 6 inches or less
  Were the levee and pond bottom areas adequately compacted
  Is the area known for sand or gravel lenses or sinkholes
  How deep is the soil
  Is there fractured or jointed bedrock in the pond basin If possible, ask the person who built the pond about potential problem areas. 
  This may help identify and reduce treatment costs. Before undertaking expensive 
  pond renovation, consider that the problem may not be seepage. If the ponds 
  watershed has been altered or reduced in size, less water may be flowing into 
  it. This would give the misleading impression that water is being lost from the 
  pond. Sometimes ponds only appear to be leaking, or they may leak only temporarily. 
  Ponds built in shrink/swell clays will develop deep cracks when dry. As they are 
  refilled, water runs through the cracks until the soil swells again. A 
  considerable volume of water may also be lost during the initial filling of a 
  pond as it soaks into the surrounding soil, giving the impression of a leak. It 
  is not uncommon for new ponds to have high initial seepage rates that decrease 
  as microbial activity and the accumulation of fine sediment and organic matter 
  help seal the pond bottom. If ponds that have sealed in this manner are dried or 
  re-worked, they may again leak excessively until the seal re-establishes. Bentonite Sodium bentonite is a highly plastic clay that expands 8 to 20 times in 
  volume when wet. It is used to fill in voids in porous soils. Bentonite has been 
  used successfully on relatively sandy soil (at least 10 to 15 percent sand) 
  where there is adequate support for the bentonite-treated layers. Calcium bentonite does not 
      swell to the same extent
      as sodium bentonite and should not be used The amount of bentonite needed varies with soil type and laboratory testing 
          is recommended to determine optimum application rates. Given its high cost, 
          bentonite is more suited to spot treatments or small ponds. For best results, spread bentonite over the pond bottom at the recommended 
  rate and mix it in with a disk or tiller to a depth of 6 inches. Moisten the 
  soil if necessary, and compact the pond bottom. Seepage will not decrease 
  immediately because the clay swells slowly. Once treated, the pond bottom should 
  be kept moist to prevent the clay from cracking and shrinking. If a pond cannot 
  be drained, granular bentonite can be used as a spot treatment over a suspected 
  seepage area. The granular form allows the bentonite to sink to the pond bottom 
  before dispersing. Spot Treatments If seepage appears localized, dig out the suspect area and cover that section 
  with a 1-foot-thick layer of compacted clay soil. Form the clay blanket with two 
  layers of soil, compacting each layer separately. When repairing leaks in dams 
  or levees, avoid making vertical cuts, as they are difficult to seal. Dam or 
  levee cuts should be made in a broad V shape so the new fill will bond with 
  existing soil as it is compacted. If a spot treatment will not work or if 
  leakage cannot be localized, the entire pond basin will require treatment. 
  Methods for complete pond basin work-overs include simple compaction, compaction 
  aided by additives, or the addition of a liner. Liners Properly installed, a liner 
    is 100 percent effective in stopping seepage For soils with high gypsum or sand content, a liner is the only option. 
  Because of the relatively high cost, liners have been used primarily for 
  ornamental ponds, water storage, fish hatcheries, and research facilities. 
  However, advances in liner technology achieved through their widespread use for 
  landfills, hazardous waste, and water storage facilities have caused prices to 
  fall. Proper liner installation is important. A liners edges usually are 
  anchored into a trench built around the pond perimeter. Many factors influence the selection of a liner material, and consumers have 
  a wide choice of products. Modern plastics are environmentally safe, withstand 
  freezing, and are UV-stabilized for long-term exposure to the sun. With care, a 
  pond liner can last 20 to 25 years. Liner thickness is measured in thousandths of an inch (mils). Twelve to 
  20-mil liners can be used in sandy soils, while thicker liners are required to 
  prevent punctures in rocky soils. In some cases, an inexpensive geotextile mat 
  is applied under the liner to protect against punctures. Liners 20 mils or less 
  in thickness are more suitable for temporary uses. For permanent aquaculture 
  facilities, 30 to 40-mil liners are recommended. Thin liners will be punctured 
  by plant sprouts along pond edges unless a sterilant is applied before the liner 
  is installed. Obviously, even thick liners must be protected to a reasonable 
  degree. For example, cattle or deer should not be allowed to trample lined 
  ponds. Liners can be made from high density polyethylene (HDPE) or low-density 
  polyethylene (LDPE). LDPE is more flexible and is used where there is more 
  shifting or movement of the soil, while HDPE is more resistant to chemicals. 
  Polyethylene is both economical and durable and can be reinforced for greater 
  strength. Seams on polyethylene liners are best sealed by heat welding or extrusion, 
  which calls for custom fabrication for smaller ponds or professional 
  installation on larger ponds. Vinyl can also be used for liners and, though less 
  resistant to aging than polyethylene, it can be sealed and patched with solvent 
  adhesives. Liners will become slippery with time, which can create a safety hazard where 
  pond slopes are steep. Using a textured plastic liner or embedding small stones 
  in the liners sides with a liquid urethane rubber product will provide a 
  non-slip surface.  New Innovative Aerator 
  for Pond Aeration
  By: 
  Aquaculture 
    Research/Environmental Assoc. (AREA), Homestead, FL. After 5 years of 
  development and being tested by universities, Modern Air Aerators are a 
  non-corrosive airlift driven aerator that will move approximately 9 million 
  gallons of water per day. This amazing aerator has no moving parts allowing for 
  maintenance free operation that will run continuous duty for at least 5 years.  
  Another benefit is that there are no electrical components in the water which 
  makes Modern Air Aerators harmless for employees.   The list below shows several advantages of the 
            Modern Air Aerators over 
  traditional pond aerators.  They include: Moves 9 Million+ Gallons Of Water Per Day
          Transfers 3.162 Lbs Of 
              Oxygen Per Hour
          Low Operating Costs 
            (Approx. $ 0.12 / Hour)
          No Moving Parts
          Continuous Operation 
            And Maintenance Free For At Least 5 Years
          100% Heavy Duty Pvc 
            Plate And Fitting Construction (Non-Corrosive)        
          No Petroleum Lubricants
        Low Noise Level ( 60 Dba)
        Easily Portable Due To 
            Being Lightweight
          Relieves Animal Stress 
            In Production Ponds
          Total Destratification 
            At Any Water Depth
          Operates In A Minimum 
            Of 4' Of Water        
          5 Year Limited Warranty
  Reference Material from 
  the
              American Fisheries Society (AFS) The books listed below represent 
      a sample of the online fish culture references published by AFS.
      Also included are selected titles from other publishers. Blue Book, Suggested Procedures for the Detection and 
    Identification of Certain Finfish and Shellfish Pathogens, Version 1
    Published by the Fish Health Section, this 4th edition contains suggested 
    procedures for the detection and identification of certain finfish and shellfish 
    pathogens. The a book is a loose-leaf format that can be quickly and easily 
    updated. Suggested Procedures for the Detection and Identification of 
    Certain Finfish and Shellfish Pathogens (Bluebook), 2004 Edition
    Originally published in loose-leaf format as the Blue Book, this updated, 
    searchable CD contains both the familiar chapters of the "Suggested Procedures 
    for the Detection and Identification of Certain Finfish and Shellfish Pathogens" 
    and the newly revised "Standard Procedures for Aquatic Animal Health 
    Inspections" co-authored by the U.S. Fish and Wildlife Service and the AFS Fish 
    Health Section. This new format allows the user to easily access information and 
    contains numerous color photographs and video clips. Published by the AFS Fish 
    Health Section. Fish Hatchery Management, Second Edition
    This second edition expands and updates the original Fish Hatchery Management, 
    the pre-eminent fish culture manual in North America since 1982, which has been
    used in universities and USFWS training centers nationwide to train new 
    generations of culturists. The new edition has been completely rewritten by 
    experts to include
    major advances in hatchery operation, in practical knowledge about raising 
    high-quality fish, and in optimal use of cultured fishes in management programs. 
    This up-to-date volume is greatly needed as a training tool and day-to-day 
    hatchery resource. Like the first edition, the book includes a great deal of 
    information about particular species, but its focus remains on the requirements 
    and practical operation of culture systems.  The new edition covers 
    advances in production, water issues, transportation, stocking, open systems, 
    controlled systems, semi-controlled systems, broodstocks and spawning, nutrition 
    and and feeding, fish health, and special considerations. Authors have developed 
    chapters for relevance to both private and public fish culture. A Manual of Fish Culture
  A Manual of Fish Culture, originally published by the 
    U.S. Commission on Fisheries in 1897, contains descriptions of culture 
    techniques for more than 40 species or groups of finfish's, plus lobsters, 
    oysters, clams, and frogs. When published, it contained all the information 
    needed by fish culturists. The techniques and practices described in the
    Manual became the standard for aquaculturists and the forerunner of the 
    technical publications of today.  This reprint of the 1897 book was 
    produced by the Fish Culture Section of the American Fisheries Society. Whirling Disease: Reviews and Current Topics
    This book is a compilation of the latest whirling disease research findings, 
    along with seven invited review papers in seven subtopics. It represents a 
    peer-reviewed version of the proceedings of the 7th Annual Whirling Disease 
    Symposium held in February 2001 in Salt Lake City, Utah. It is also much more 
    than that, given the value of its extensive and thoroughly researched review 
    papers. The volume will be a valuable resource for researchers in the field as 
    well as a reference volume for managers who have to make decisions on 
    controlling whirling disease.  **Return
        to MTAN selection page
        Return to Ashland FRO home page
        Return to Region 3 U.S. Fish and Wildlife Service**  Product and company
      names mentioned in this publication are for informational purposes only.
      It does not imply endorsement by the MTAN or the U.S. Government.
 Last updated: 
        February 3, 2009
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