U.S. ENVIRONMENTAL PROTECTION AGENCY NATIONAL EUTROPHICATION SURVEY WORKING PAPER SERIES REPORT ON SPIRIT LAKE DICKINSON COUNTY IOW EPAEGIONVII WORKING PAPER No, 506 CORVALLIS ENVIRONMENTAL RESEARCH LABORATORY - CORVALLIS, OREGON and ENVIRONMENTAL MONITORING & SUPPORT LABORATORY - LAS VEGAS, NEVADA "WTG.P.O. 699-440 ------- REPORT ON SPIRIT LAKE DICKINSON COUNTY IOWA EPA REGION VII WORKING PAPER No, 506 WITH THE COOPERATION OF THE IOWA DEPARTMENT OF ENVIRONMENTAL QUALITY AND THE IOWA NATIONAL GUARD AUGUST, 1976 ------- CONTENTS Page Foreword ii List of Iowa Study Lakes iv Lake and Drainage Area Map v Sections I. Introduction 1 II. Conclusions 2 III. Lake and Drainage Basin Characteristics 4 IV. Lake Water Quality Summary 5 V. Literature Reviewed 9 VI. Appendices 10 ------- 11 FOREWORD The National Eutrophication Survey was initiated in 1972 in response to an Administration commitment to investigate the nation- wide threat of accelerated eutrophication to freshwater lakes and reservoirs. OBJECTIVES The Survey was designed to develop, in conjunction with state environmental agencies, information on nutrient sources, concentrations, and impact on selected freshwater lakes as a basis for formulating comprehensive and coordinated national, regional, and state management practices relating to point-source discharge reduction and non-point source pollution abatement in lake watersheds. ANALYTIC APPROACH The mathematical and statistical procedures selected for the Survey's eutrophication analysis are based on related concepts that: a. A generalized representation or model relating sources, concentrations, and impacts can be constructed. b. By applying measurements of relevant parameters associated with lake degradation, the generalized model can be transformed into an operational representation of a lake, its drainage basin, and related nutrients. c. With such a transformation, an assessment of the potential for eutrophication control can be made. LAKE ANALYSIS In this report, the first stage of evaluation of lake and water- shed data collected from the study lake and its drainage basin is documented. The report is formatted to provide state environmental agencies with specific information for basin planning [§303(e)J, water quality criteria/standards review [§303(c)L clean lakes [§314(a,b)], and water quality monitoring [§106 and §305(b)] activities mandated by the Federal Water Pollution Control Act Amendments of 1972. ------- Ill Beyond the single lake analysis, broader based correlations between nutrient concentrations (and loading) and trophic condi- tion are being made to advance the rationale and data base for refinement of nutrient water quality criteria for the Nation's freshwater lakes. Likewise, multivariate evaluations for the relationships between land use, nutrient export, and trophic condition, by lake class or use, are being developed to assist in the formulation of planning guidelines and policies by EPA and to augment plans implementation by the states. ACKNOWLEDGMENT The staff of the National Eutrophication Survey (Office of Research & Development, U. S. Environmental Protection Agency) expresses sincere appreciation to the Iowa Department of Environ- mental Quality for professional involvement, to the Iowa National Guard for conducting the tributary sampling phase of the Survey, and to those wastewater treatment plant operators who voluntarily provided effluent samples and flow data. The staff of the Water Quality Division of the Department of Environmental Quality provided invaluable lake documentation and counsel during the Survey, reviewed the preliminary reports, and provided critiques most useful in the preparation of this Working Paper series. Major General Joseph G. May, the Adjutant General of Iowa, and Project Officer Colonel Cleadeth P. Woods, who directed the volunteer efforts of the Iowa National Guardsmen, are also grate- fully acknowledged for their assistance to the Survey. ------- iv LAKE NAME Ahquabi Big Creek Reservoir Black Hawk Clear Darling Lost Island MacBride Prairie Rose Rathbun Reservoir Red Rock Reservoir Rock Creek Silver Spirit Vi king West Okoboji NATIONAL EUTROPHICATION SURVEY STUDY LAKES STATE OF IOWA COUNTY Warren Polk Sac Cerro Gordo Washington Clay, Palo Alto Johnson Shelby Appanoose, Wayne Marion Jasper Worth Dickinson Montgomery Dickinson ------- MINNESOTA WESTOKOBOJI LAKE & SPIRIT LAKE X Lake Sampling Site 0 1234 1 2 Scale s Km. 3Mi. 43'3tf~ 4320— 9510 9500' ------- SPIRIT LAKE STORE! NO. 1913 I. INTRODUCTION*: Spirit Lake was included in the National Eutrophication Survey as a water body of interest to the Iowa Department of Environmental Quality. Tributaries and nutrient sources were not sampled, and this report relates only to the lake sampling data. Spirit Lake is one of a chain of natural lakes collectively known as the Iowa Great Lakes. Glacial in origin, the lake is quite shallow but has the largest surface area of any of the natural lakes in the state. Besides being used as a public water supply, it is a valuable recreational asset. Activities such as camping, fishing, and swimming attract many Iowa residents and out-of-state visitors; and private residences, cabins, and commercial establishments ring the shoreline. Abundant gamefish present include perch, smallmouth and largemouth bass, and walleyes. Some bluegills, crappies, and channel catfish can also be caught. The watershed is almost entirely agricultural. All of the Iowa Great Lakes have been classified as eutrophic but in varying degrees. Nuisance algal blooms are most severe in Lower Gar Lake and Lake East Okoboji, although all of the lakes have summer algae problems. There has been an apparent decrease of macrophyte and muolTuscan species diversity in recent years, as well as an increase in the abundance * Description of the lake from Bachmann and Jones (1974). ------- 2 of blue-green algae. However, sediment core samples indicate that the Iowa Great Lakes chain has been eutrophic for several thousand years. It has been estimated that the lake chain as a whole receives only 3% of the total phosphorus load from urban sources with the remainder contributed by agricultural runoff and other non-point sources; feedlots contribute about 10% of the phosphorus load to Spirit Lake. II. CONCLUSIONS A. Trophic Condition: Survey data indicate that Spirit Lake is eutrophic. It ranked first in overall trophic quality when the 15 Iowa lakes and reservoirs sampled in 1974 were compared using a combination of six water quality parameters*. However, based on their more extensive studies, Bachman and Jones (op. cit.) consider West Okoboji Lake to be of better overall trophic quality than Spirit Lake. None of the other Iowa water bodies had less median total phosphorus and median orthophosphorus, three had less median inor- ganic nitrogen and mean chlorophyll a_, and two had greater mean Secchi disc transparency. Survey limnologists observed some surface phytoplankton during the July sampling at all stations. B. Rate-Limiting Nutrient: The algal assay results indicate that Spirit Lake was phos- * See Appendix A. ------- 3 phorus limited at the time the sample was collected (04/23/74). The lake data indicate phosphorus limitation at stations 1 and 2 in April but nitrogen limitation at station 3. Nitrogen limi- tation is indicated at all three stations in September. ------- III. LAKE AND DRAINAGE BASIN CHARACTERISTICS1" A. Lake Morphometry : 1. Surface area: 23.00 kilometers2. 2. Mean depth: 5.5 meters. 3. Maximum depth: 7.3 meters. 4. Volume: 126.500 x 106 m3. 5. Mean hydraulic retention time: Unknown. C. Precipitation*: 1. Year of sampling: 71.8 centimeters. 2. Mean annual: 70.5 centimeters. t Table of metric conversions—Appendix B. tt Harrison, 1975. * See Working Paper No. 175, "...Survey Methods, 1973-1976", ------- 5 IV. LAKE WATER QUALITY SUMMARY Spirit Lake was sampled three times during the open-water season of 1974 by means of a pontoon-equipped Huey helicopter. Each time, samples for physical and chemical parameters were collected from one or more depths at three stations on the lake (see map, page v). During each visit, a single depth-integrated (near bottom to surface) sample was composited from the stations for phytoplankton identification and enumeration; and during the first visit, a single 18.9-liter depth- integrated sample was composited for algal assays. Also each time, a depth-integrated sample was collected from each of the stations for chlorophyll ^analysis. The maximum depths sampled were 4.6 meters at station 1, 4.9 meters at station 2, and 4.6 meters at station 3. The sampling results are presented in full in Appendix C and are summarized in the following table (the July nutrient samples were not preserved properly and were not analyzed). ------- PARAMETER TEMP (C) DISS OXY (MG/L> CNDCTVY (MCROMO) PH (STAND UNITS) TOT ALK (MG/L) TOT P (MG/L> ORTHO P (MG/L) N02»N03 (MG/L) AMMONIA (MG/L) KJEL N (MG/L) INORG N (MG/L) TOTAL N (MG/L) CHLBPYL A (UG/L) SECCHI (METERS) A. SUMMARY OF PHYSICAL AND 1ST SAMPLING ( 4/23/74) 3 SITES CHEMICAL CHARACTERISTICS FOR SPIRIT LAKE STORET CODE 1913 2ND SAMPLING ( 7/ 9/74) 3 SITES 3RD SAMPLING ( 9/23/74) 3 SITES RANGE 8.5 - 10.0 - 332. - 8.4 186. 0.030 0.002 0.080 0.030 0.900 0.120 0.990 2.3 2.7 - - 0 - 0 - 1 - 0 • 1 - 8.7 10.6 337. 8.4 193. .049 • 019 .110 .050 .100 • 160 .210 2.6 3.7 MEAN 8.6 10.3 335. 8.4 191. 0.037 0.007 0.097 0*041 0«967 0.138 1.063 2.5 3.1 MEDIAN RANGE MEAN MEDIAN 8.7 24.1 - 24.9 24.6 24.6 10.3 6.0 - 8.2 7.6 8.0 335. 544. - 555. 549. 548. 0 0 0 0 1 0 1 8.4 8.6 - 8.7 8.6 8.6 .034 «•••»» -««•«•»*>•«»«•*»•«>***• 2.5 13.8 - 15.4 14.6 14.7 3.0 1.5 - 1.5 1.5 1.5 0 0 0 0 1 0 1 RANGE 15.2 - 9.0 - 367. - 8.3 167. .038 .006 .020 .020 .200 .040 .220 19.5 1.1 - - 0 - 0 - 0 - 0 - 1 - 0 - 1 - 15.5 9.4 369. 8.4 182. .058 .013 .030 .040 .400 .060 .420 22.4 1.4 MEAN 15.3 9.2 368. 8.4 174. 0.045 0.009 0.021 0.030 1.278 0.051 1 .299 20.8 1.2 MEDIAN 15.3 9.2 368. 8.4 173. 0.043 0.009 0.020 0.030 1.300 0.050 1.320 20.4 1.2 ------- B. Biological Characteristics: 1. Phytoplankton - Sampling Date 04/23/74 07/09/74 09/23/74 2. Chlorophyll a_ - Sampling Date 04/23/74 07/09/74 09/23/74 Dominant Genera 1. Flagellates 2. Dinobryon sp. 3. Cryptomonas sp. 4. Aphanothece sp. 5. Dinoflagellates Other genera Total 1. Aphanocapsa sp. 2. Aphanizomenon sp. 3. Schroederia sp. 4. Anabaena sp. 5. Cryptomonas sp. Other genera Total 1. Aphanothece sp. 2. Anabaena sp. 3. Aphanizomenon sp. 4. Coelosphaerium sp. 5. Oscillatoria sp. Other genera Total Station Number 1 2 3 1 2 3 1 2 3 Algal Units per ml 912 240 144 96 48 97 1,537 1,569 262 262 232 145 174 2,644 1,182 734 326 285 245 937 3,709 Chlorophyll a_ (yg/1) 2.6 2.3 2.5 15.4 14.7 13.8 22. 20. 19.5 ------- 8 Limiting Nutrient Study: 1. Autoclaved, filtered, and nutrient spiked - Ortho P Inorganic N Maximum yield Spike (mg/1) Cone, (mg/1) Cone, (mg/1) (mg/l-dry wt.) Control 0.005 0.109 0.1 0.050 P 0.055 0.109 3.1 0.050 P + 1.0 N 0.055 1.109 16.1 1.0 N 0.005 1.109 0.1 2. Discussion - The control yield of the assay alga, Selenastrum capri- cornutum, indicates that the potential primary productivity of Spirit Lake was low at the time the assay sample was taken (04/23/74). The results also indicate phosphorus limi- tation at that time. Note the significant increase in yield when only orthophosphorus was added and the lack of yield response when only nitrogen was added. The lake data indicate phosphorus limitation in April at stations 1 and 2; i.e., the mean inorganic nitrogen to ortho- phosphorus ratios were 45 to 1 and 33 to 1, respectively. However, nitrogen limitation is- indicated at station 3 (the mean N/P ratio was 11/1). The September lake data indicate nitrogen limitation at all stations; i.e., the mean N/P ratios were 6/1 or less, and nitrogen limitation would be expected. ------- V. LITERATURE REVIEWED Anonymous, 1974. Management plan for water quality—Iowa Great Lakes. E. A. Hickok and Assoc., Wayzata, Minnesota. Bachmann, Roger W., and John R. Jones, 1974. Water quality in the Iowa Great Lakes. MS, Dept. of Zoo. & Ent., IA St. U., Ames. Harrison, Harry M., 1975. Personal communication (lake morphometry). IA Cons. Comm., Des Moines. ------- VI. APPENDICES APPENDIX A LAKE RANKINGS ------- LAKE DATA TO BE USED IN RANKlNGb LAKE CODE LAKE NAME 1901 LAKE ACOUA6I 1902 8IG CREEK RESERVOIR 1903 SLACK HAWK LAKE 1904 CLEAR LAKE 1905 LAKE DARLING 1906 LOST ISLAND LAKE 1907 LAKE MACBPIOE 1908 PRAIRIE ROSE LAKE 1909 RATHBUN RESERVOIR 1910 RED ROCK LAKE 1911 ROCK CREEK LAKE 1912 SILVER LAKE 1913 SPIRIT LAKE 1914 VIKING LAKE 1915 WEST LAKE OKOBOJI MEDIAN TOTAu H 0.06? 0.046 0.185 0.059 0.077 0.146 0.061 0.056 0.071 0.180 0.065 0.193 0.041 0.075 0.046 MEDIAN 1NO«G N 0.3J5 6.465 0.130 0.070 1.475 0.065 2.035 0.210 1.170 1.880 1.400 0.565 0.090 0.130 0.060 500- MEAN SEC 469.333 436.500 488.167 465.125 482.500 421.167 458.444 463.667 475.889 473.400 480.500 482.667 422.667 459.000 380.444 MEAN CuLOrtA 8.600 16.867 49.740 17.400 13.817 36.100 17.067 17.350 12.039 14.730 18.367 95.300 12.622 26.033 7.722 15- HIN DO 8.200 14.800 15.000 8.600 9.200 8.400 15.000 8.600 14.000 14.000 8.400 10.000 9.000 14.200 15.000 MEDIAN DISS OKTrtO P 0.009 0.011 0.020 0.010 0.012 0.021 0.010 0.010 0.008 0.104 0.007 0.034 0.007 0.017 0.017 ------- PERCENT OF LAKES WITH HIGHER VALUES (NUMBER OF LAKES WITH HIGHER VALUES) LAKE CODE LAKE NAME 1901 LAKE ACOUABI 190? BIG CREEK RESERVOIR 1903 BLACK HAWK LAKE 1904 CLEAR LAKE 1905 LAKE DARLING 1906 LOST ISLAND LAKE 1907 LAKE MACBRIDE 1908 PRAIRIE ROSE LAKE 1909 RATHBUN RESERVOIR 1910 RED ROCK LAKE 1911 ROCK CREEK LAKE 1912 SILVER LAKE 1913 SPIRIT LAKE 191* VIKING LAKE 1915 WEST LAKE OKOBOJI MEDIAN TOTAL P 57 ( 69 ( 7 ( 71 ( 29 ( 21 ( 64 ( 79 ( 43 ( 1* ( 50 ( 0 ( 100 ( 36 ( 89 ( 8) 12) 1) 10) 4) 3) 9) 11) 6) 2) 7) 0) 14) 5) 12) MEDIAN INO*G N 50 ( 0 ( foB ( 86 ( 21 ( 93 ( 7 ( 57 ( 36 ( 14 ( 29 < 43 < 79 ( 68 ( 100 ( 7) 0) 9) 12) 3) 13) 1) 8) 5) 2> 4) 6) 11) 9) 14) 500- MEAN SEC 43 ( 79 ( 0 ( 50 ( 14 ( 93 ( 71 ( 57 ( 29 ( 36 ( 21 ( 7 ( 86 ( 64 ( 100 ( 6) 11) 0) 7) 2) 13) 10) 8) 4) 5) 3) 1) 12) 9) 14) MEAN CHLORA 93 ( 57 ( 7 ( 36 ( 71 ( 1* ( 50 < 43 < 86 ( 64 ( 29 ( 0 ( 79 ( 21 ( 100 ( 13) 8) 1) 5) 10) 2) 7) 6) 12> 9) 4) 0) 11) 3) 14) 15- MIN DO 100 21 7 75 57 89 7 75 39 39 89 50 64 29 7 I 14) ( 3) ( 0) ( 10) ( 8) ( 12) ( 0) ( 10) ( 5) ( 5) ( 12) < 7) ( 9) ( 4) ( 0) MEDIAN DISS ORTHO P 79 ( 50 ( 21 ( 64 < 43 ( 14 ( 64 ( 64 { 86 ( 0 ( 96 < 7 ( 96 ( 32 ( 32 ( 11) 7) 3) 8) 6) 2) 8) 8) 12) 0) 13) 1) 13) 4) 4) INDEX NO 422 296 110 382 235 324 263 375 319 167 314 107 504 250 428 ------- LAKES RANKED 8V INDEX NOS. RANK LAKE CODE LAKE NAME INDEX NO 1 1913 SPIRIT LAKE 504 2 1915 WEST LAKE OK080JI 428 3 1901 LAKE ACOUABI 422 4 1904 CLEAR LAKE 382 5 1908 PRAIRIE ROSE LAKE 375 6 1906 LOST ISLAND LAKE 324 7 1909 RATHBUN RESERVOIR 319 8 1911 ROCK CREEK LAKE 314 9 1902 BIG CREEK RESERVOIR 296 19 1907 LAKE MACBRIDE 263 11 1914 VIKING LAKE 250 12 1905 LAKE DARLING 235 13 1910 RED ROCK LAKE 167 14 1903 BLACK HAWK LAKE 110 15 1912 SILVER LAKE 107 ------- APPENDIX B CONVERSION FACTORS ------- CONVERSION FACTORS Hectares x 2.471 = acres Kilometers x 0.6214 = miles Meters x 3.281 = feet Cubic meters x 8.107 x 10 = acre/feet Square kilometers x 0.3861 = square miles Cubic meters/sec x 35.315 = cubic feet/sec Centimeters x 0.3937 = inches Kilograms x 2.205 = pounds Kilograms/square kilometer x 5.711 = Ibs/square mile ------- APPENDIX C PHYSICAL and CHEMICAL DATA ------- STOREf RETRIEVAL DATE 7b/l'J/21 191301 43 27 21.0 095 06 08.0 SPIRIT LAKE 19 IOWA DATE TIME DEPTH FROM OF TO DAY FEET 74/04/23 10 00 0000 10 00 0005 10 00 0015 74/07/09 14 ?5 0000 14 25 0005 14 25 0015 74/^9/23 14 55 0000 14 55 0005 14 55 0014 11EPALES 3 2111202 0019 FEET DEPTH 00010 WATER TtMP CENT 8.7 8.7 8.7 24.7 24.6 24. 1 15.3 15.3 15.3 00300 00 MG/L 10.4 10.4 6.0 a.o 7.6 9.0 9.4 9.2 00077 TRANSP SECCHI INCHES 108 60 54 00094 CNDUCTVY FIELD MICROMHO 336 334 337 555 552 553 368 368 368 00400 PH SU 8.40 8.40 8.40 8.60 8.60 8.60 8.32 8.34 8.39 00410 T ALK CAC03 MG/L 186 190 192 173 176 173 00610 NH3-N TOTAL MG/L 0.040 0.040 0.040 0.030 0.030 0.030 00625 TOT KJEL N MG/L 0.900 0.900 1.000 1.300 1.-300 1.400 00630 N02&N03 N-TOTAL MG/L 0.100 0.110 0.090 0.020K 0.020 0.020 00671 PHOS-DIS ORTHO MG/L P 0.002 0.006 0.004 0.006 0.008 0.012 DATE TIME DEPTH FROM OF TO DAY FEET 74/04/23 10 00 0000 10 00 0005 10 00 0015 74/07/09 14 ?5 0000 74/09/23 14 55 0000 14 55 0005 14 55 0009 14 55 0014 J665 'b-TOf i/L P O.C31 C.043 0.049 •j.03d 0.041 32217 CHLRPHYL A 'UG/L 2.6 15.4 2?. 4 00031 INCOT LT REMNING PERCENT 1.0 u.043 K VALUE KNOWN TO BE LESS THAN INDICATED ------- STORET RETRIEVAL DATE 75/10/21 191302 43 29 03.0 095 06 18.0 SPIRIT LAKE 19 IOWA DATE FROM TO 74/04/23 74/07/09 74/09/23 TIME DEPTH OF (JAY FEET 10 20 0000 10 20 0005 10 20 0016 14 49 0000 14 49 0005 14 49 U016 14 00 0000 14 00 0005 14 00 0015 00010 •HATER TEMP CENT 8.7 8.7 8.7 24.6 ?4.b 24.3 15.2 15.2 15.2 00300 00077 00094 DO TRANSP CNDUCTVY SECChI HELD MG/L INCHES MICROMHO 10.0 10.0 6.2 7.2 7.2 9.2 9.2 9.2 144 60 42 335 335 3J6 550 548 547 367 367 368 11EPALES 3 00^00 PH ill 8.40 8.40 8.40 8.60 8.60 8.60 8.39 8.40 8.40 00410 T ALK CAC03 MG/L 190 192 192 182 167 172 211 0020 00610 NH3-N TOTAL Mli/L 0.050 0.040 0.040 0.030 0.030 0.030 1202 FEET DEPTH 00625 TOT KJEL N MG/L 0.900 0.900 1.000 1.300 1.200 1.200 (JO 630 N02&N03 N-TOTAL MG/L 0.100 0.090 0.080 0.020K 0.030 0.020K 00671 PMOS-iDIS URTriO MG/L P 0.004 0.004 0.004 0.013 0.009 0.012 00665 DATE TIME DEPTH PHOS-TOT FROM OF TO DAY FtET MG/L P 74/04/23 10 20 0000 0.030 10 20 0005 0.03d 1U 20 0016 0.030 74/07/09 14 49 0000 74/09/23 14 00 0000 0.05s 14 00 0005 u.U<*5 14 00 0009 14 00 0015 0.0«8 32217 00031 CHLRPHYL INCDT LT A REMNING UG/L PERCENT 2.3 14.7 20.4 1.0 K VALUE KNOWN TO BE LESS THAN INDICATED ------- STORET RETRIEVAL DATE 75/10/21 191303 43 29 20.0 095 03 58.0 SPIRIT LAKE 19 IOWA DATE FROM TO 74/04/23 74/07/09 74/09/23 TIME OEPTH OF DAY FEET 10 35 0000 10 35 0005 10 35 0014 15 13 0000 15 13 U005 15 13 0014 14 30 0000 14 30 0005 14 30 OOlb 00010 WATER TEMP CENT 8.5 8.6 8.5 24.9 24.8 24.6 15.5 15.4 15.4 00300 OOC77 00094 DO TRANSP CNDUCTVY SECCHI FIELD MG/L INCHES M1CHOMHO 1C.2 10.6 8.0 8.0 8.0 9.4 9.2 9.4 120 60 48 334 334 332 544 544 544 368 368 369 11EPALES 3 00400 PH SU 8.40 8.40 8.40 8.70 8.70 8.70 8.40 8.37 8.39 00410 T ALK CAC03 MG/L 193 193 193 173 173 173 211 0018 00610 NH3-N TOTAL MG/L 0.050 0.040 0.030 0.030 0.040 0.020 1202 FEET OEPTH 00625 TOT KJEL N MG/L 1.100 1.000 1.000 1.300 1.300 1.200 00630 N02&N03 N-TOTAL MG/L 0.110 0.100 0.090 0.020K 0.020K 0.020K 00671 PHOS-DIS ORTHO MG/L P 0.019 0.013 0.006 0.007 0.009 0.008 DATE TIME OEPTH FROM OF fU DAY FEET 74/04/23 10 35 0000 10 35 0005 10 35 0014 74/0 7/09 15 13 0000 74/09/23 14 30 0000 14 30 0005 14 30 0009 14 30 0015 D066S JS-TUT 3/L P 0.033 U.042 0.034 0.040 0.042 32217 CHLRPHYL A UG/L 2.5 13.8 19.5 00031 INCDT LT REMNING PERCENT ' 1.0 ).04b K VALUE KNOWN TO BE LESS THAN INDICATED ------- |