United States Department of National Agriculture Soil Engineering Conservation Service Handbook Section 3 Sedimentation Chapter 9 Units and General ................................................................................. 9-1 Metric system (81) conversion ................................................................ 9-1 L Rules for style and usage ................................................................. 9-2 Conversionfactors ....................................................................... 9-2 Other conversions ......................................................................... 9-8 References ............................................................................... 9-15 Figures Page 9-1. Conversion of tons to acre-feet for various volume-weights.. 9-9 Tables Page 9-1. Base units of the International System (SI) . 9-1 9-2. Prefixes for use in multiples of International System (SI) units. 9-2 9-3. Conversion factors for hydraulic volumes . 9-11 9-4. Greekalphabet ...................................................................... 9-11 9-5. Map scales and area equivalents . 9-12 9-6. Volume-weight conversions . 9-13 9-7. Conversion of inches to feet . 9-14 Chapter 9 Units and Equivalents General Metric System (SI) Conversion Various lists, tables, and charts are included in Most of the procedures, formulas, and tables in this section for the convenience of geologists com- this handbook are presented in English units. Con- 'b piling information on rates, volumes, and quan- version factors are included in this chapter for tities of sediment, rock formations, and geologic those who wish to use the metric system. Table 9-1 processes. The only explanations in the tables and shows pertinent base units of the International charts are those necessary to give the basis for the System of Units (SO, and table 9-2 shows prefixes information presented. The conversion factors to be used with SI units. shown are generally four significant digits; more precise conversion factors of five or more signifi- cant digits may be needed in some instances. In all Table 9-1.-Base units of the International System (SI) conversions, retain enough significant digits to en- sure that accuracy is neither sacrificed nor Base unit exaggerated. Quantity Name Symbol Length meter (metre)' m MassZ kilogram kg Time second s 'Both spelling are acceptable. =Weight is the commonly used term for mass. Table 9-2.-Prefixes for use in multiples of International Rules for Style and Usage System (SI) units Mutiplier Prefix Symbol The choice of the appropriate prefix (multiplierhi of an SI unit is governed by convenience. The 10l8 exa E 10l6 peta P multiple chosen for a particular application is the 10" tera T one that yields numerical values within a practical los G range. 1O6 mega M Use a slash (0 to form a compound unit by lo8 kilo k dividing one unit by another, e.g., mh, kg/ma. lo2 hectoa h 10' dekaa da Area or volume units are indicated by the ap- 10-I decia d propriate superscript, e.g., kma or m3. 10" centia c Do not use multiple prefixes, such as dkm or pml. milli m lo-% micro Cc lo4 nano n 10-l2 pic0 P 10-l6 femto f 10-l8 atto a Fl'hese prefixes are generally not recommended. Multiples of 1,000 are preferred. Conversion Factors To Convert Into Multiply By A acre hectares or square hectometers 0.4047 square feet ($q ft)a 43,560. square meteds (ma) 4,047. square miles (sq mi) 1.562 x acre-feet (acre-ft) cubic feet (cu ft) 43,560 cubic yards (cu yd) 1,613. gallons (gal) 325,850. megaliters (ML) 1.234 cubic meters (ms) 1,234. cubic dekameters (dams) 1.234 acre-inches 12.00 acre-feetlsquare mile cubic feetlacre 68.06 (acre-ftlsq mi) tonslsquare mile (Tlsq mi) See fig. 9-1 tonslacre See fig. 9-lb watershed inches 0.01875 cubic meterslsquare kilometer (ms/kma) 476.3 acre-feet of water tons 1,359. cubic dekameters (dams) 1.234 megagrams (Mg) 1,234. 'These abbreviations may be used when their meaning is clear; otherwise spell them out. b~ftergetting tondsquare mile from figure 9-1, multiply by 1.56 x to con- vert to tonduere. To Convert -Into Multiply By L acre-inches acre-feet (acre-&) 0.08333 cubic feet (cu ft) 3,630. C Celsius (C) Fahrenheit (F) centimeters (cm) feet (ft) inches (in) meters (m) millimeters (mm) centimeterstsecond (cmls) feetlminute (ftlmin) cubic centimeters (cmS) cubic feet (cu ft) cubic inches (cu in) U.S. gallons (US. gal) liters (L) U.S. pints U.S. quarts cubic dekameters (dams) acre-feet (acre-ft) cubic feet (cu ft) cubic centimeters (cmS) cubic inches (cu in) cubic meters (m3) cubic yards (cu yd) U.S. gallons (U.S. gal) liters (L) cubic feettacre acre-inches acre-feet (acre-ft) cubic feet of water pounds (Ib) L kilogramstsquare centimeter (kg/cma) kilogramstsquare meter (kg/m2) poundstsquare foot (psf) poundstsquare inch (psi) cubic feettsecond (cfs) acre-feet per day (acre-fttd) acre-feet per year (acre-ft/yr) gallonstminute (gpm) million gallonstday (mgd) cubic meterstsecond (ms/s) literstsecond (Lts) cubic feet/second/square liters/second~squarekilometer mile (csm) (L/s/kma) cubic feetlsecond-days cubic feet cubic inches (cu in) cubic centimeters (cmS) cubic feet (cu ft) cubic meters (ms) cubic feet (cu ft) U.S. gallons (U.S. gal) cubic yards (cu yd) cubic meterstsecond (mS/s) million gallonstday (M galld) cubic meterstsquare acre-feettsquare mile kilometer (ms/kma) cubic mile (U.S. statute) acre-feet (acre-ft) cubic yards (cu yd) cubic centimeters (cms) To Convert -Into Multiply By cubic feet (cu ft) cubic meters (mS) acre-feet (acre-ft) D days seconds (s) degrees Fahrenheit (F) degrees Celsius (C) F Fahrenheit (F) Celsius (C) feet (ft) centimeters (cm) kilometers (km) feet (ft) meters (m) miles (mi) centimeterstsecond (cds) feettsecond (fps) kilometershour (kmh) miledhour (mih) feetlsecond (fps) meterstminute (mlmin) meterstsecond (ds) mileshour (mph) kilometershour (kmh) G gallons (U.S.) cubic centimeters (cm3) cubic feet (cu ft) cubic inches (cu in) cubic meters (mS) gallons-British Imperial (gal Br. Imp.) liters (L) gallons of water pounds of water gallonstminute (gpm) cubic feettsecond ' (ds) cubic meterstday (m3/d) literstsecond (Lts) cubic feethour (cu fth) grams pounds (Ib) 2.205 x grams of water cubic centimeters of water 1.0 (at 4°C) (cm3 of H,O) gramstcubic centimeter kilograms/cubic meter (kg/m3) (gtcm3) gramstcubic meter (g/m3) partstmillion (ppm) H hectares acres square feet (sq ft) hours (h) days (d) weeks (wk) True within 1 percent when concentr* tion is less than 1,000 ppm (g/m8 = mg/L). To Convert Into Multiply By 1 inches (in) centimeters (cm) 2.540 inches (watershed) cubic feet/second/square mile (csm) 13.584 inches eroded tons (t)d 1.815 x volume wt (pcD of up- land soil K kilograms (kg) pounds, avoirdupois (lb) tons (T) megagrams (Mg) or tonnes kilograms/second (kglsec) tondyear (Tlyr) kilograms/cubic meter pounds/cubic foot (pcf) (kglms) kilometers (km) miles (mi) L liters (L) cubic centimeters (cma) cubic feet (cu ft) gallons (gal) liters/second cubic feet/second (cfs) liters/second/square cubic feet/second/square mile (csm) kilometer (L/s/km2) M megagrams (Mg) tons (T) megagramslsquare kilometer tons/square mile (Mgkm2) megaliters (ML) acre-feet (acre-ft) meters (m) yards O.d) feet (ft) inches (in) miles, U.S.Stat. (mi) meters/second (rnfs) feetlsecond (fttsec) micrometer bm) meters (m) cubic dekameters (dams) miles, U.S. Stat. (mi) kilometers (km) mileshour (mph) feet/second (fps) milliliters (ml) liters (L) millimeters (mm) inches (in) micrometers (pn) million gallons/day (mgd) cubic feetlsecond (cfs) acre-feettday cubic/meters/minute (ma/min) minutes, angular (mid degrees (deg) d~onsmeans short tons (2,000 lb) unless otherwise indicated To Convert -Into Multiply By 0 ounces (02) grams (g) pounds (lb) ounceslgallon (U.S.) gramsfliter (gm/L) (ozlgal-U.S.) P parts per million (ppm) gramslcubic meter (glm? pounds (lb) grains grams (g) kilograms (kg) ounces (02) tons pounds of water cubic feet (cu ft) cubic inches (cu in) gallons (gal) pounds of waterlminute cubic feetlsecond (cfs) poundslcubic foot (pcf) gramslcubic centimeter (g/cmS) kilogramslcubic meter (kglms) poundslcubic inch gramslcubic centimeter (g/cma) poundslgallon (U.S.) gramsfliter (g/L) poundslcubic foot (pd) tonslacre-foot (Tlacre-ft) kilogramslcubic meter (kg/ms) poundslsquare foot (psf) poundslsquare inch (psi) pounds/second~foot kilogramslsecond/meter R rods feet (ft) miles (mi) S seconds (s) days square centimeters (cma) square inches (sq in) square feet (sq ft) acres square meters (ma) square inches (sq in) square centimeters (cmP) square kilometers (kml) square miles (sq mi) acres square meters (ma) square feet (sq ft) square yards (sq yd) square miles (sq mi) acres square feet (sq ft) square kilometers &ma) square meters (ma) square yards (sq yd) square yards (sq yd) square feet (sq ft) square meters (ma) e!l"rue within 1 percent when concentra. tion is less than 10,000 ppm (g/ma = mg/L). To Convert -Into Multiply By tonnes tons 1.103 pounds Ob) 2,205. megagrams (Mg) 1.000 tons (long) pounds Ob) 2,240. tons 1.102 pounds Ob) 2,205. tons kilograms (kg) 907.2 megagrams (Mg) 0.9072 pounds (lb) 2,000. tons (long) 0.8929 tonnes 0.9072 tonslsquare mile acre-feetlsquare mile See fig. 9-1A and B (acre-ftlsq mi) megagramslsquare kilometer (MgM) tonslacre (Tlacre) tons of water124 hr pounds of waterhour gallonslminute (gpm) cubic feetlhour (cu ftthr) tonslacre-foot poundslcubic foot (pcf) W watershed inches acre-feetlsquare mile (acre-ftlsq mi) 53.33 acre-feet (total) 53.33 x drainage area in sq mi Other Conversions Figures 9-1A and 9-1B are charts for converting various volume-weights or weights of sediment per acre-foot to tons. Table 9-3 is convenient for con- versions of hydraulic or sedimentation data. Table 9-4 shows the Greek alphabet. Table 9-5 shows map scales and equivalents for use with aerial photographs and U.S.