Data on the Quantity and Chemical Quality of Precipitation

Data on the Quantity and Chemical Quality of Precipitation, Catoctin Mountain, North-Central Maryland, 1982-91

By Karen C. Rice, Margaret M. Kennedy, Owen P. Bricker, and Colleen A. Donnelly

U.S. GEOLOGICAL SURVEY

Open-File Report 93-169

Prepared in Cooperation with the National Acid Precipitation Assessment Program, the Maryland Department of the Environment, and the Maryland Department of Natural Resources

Towson, Maryland 1993

U.S. DEPARTMENT OF THE INTERIOR BRUCE BABBITT, Secretary

U.S. GEOLOGICAL SURVEY Robert M. Hirsch, Acting Director

For additional information write to:

Area Assistant Regional Hydrologist, U.S. Geological Survey, WRD 8600 LaSalle Rd, 208 Carroll Bldg. Towson, MD21286

Copies of this report can be purchased from:

U.S. Geological Survey Earth Science Information Center Open-File Reports Section Box25286, MS 517 Denver Federal Center Denver, CO 80225

CONTENTS

Abstract................................................................................................ 1Introduction............................................................................................. 1

Purpose and scope................................................................................. 1Description of study area ........................................................................... 1

Acknowledgments ................................................................................ 3

Collection and analysis of data .............................................................................. 3

Instrumentation of precipitation-collection station ....................................................... 3Field data-collection methods........................................................................ 3Laboratory-analysis methods and instrumentation. ....................................................... 4

Data on quantity of precipitation. ............................................................................ 5Data on chemical quality of precipitation...................................................................... 5Summary of precipitation data .............................................................................. 6Selected references ....................................................................................... 9

FIGURES

1. Map showing location of the U.S. Geological Survey precipitation-collection station at Catoctin Mountain,Maryland........................................................................................ 2

2. Graph showing annual precipitation-weighted mean field hydrogen-ion concentrations.......................... 7

3. Graph showing annual precipitation-weighted mean concentrations of sum of base cations, sulfate, and nitrate. ...... 7

TABLES

1-10. Quantity of daily precipitation collected from the U.S. Geological Survey precipitation-collection station at Catoctin Mountain, Maryland, in:

1. 1982........................................................................................... 12

2. 1983........................................................................................... 13

3. 1984........................................................................................... 14

4. 1985........................................................................................... 15

5. 1986........................................................................................... 16

6. 1987........................................................................................... 17

7. 1988........................................................................................... 18

8. 1989........................................................................................... 19

9. 1990........................................................................................... 20

10. 1991........................................................................................... 21

11. Quantity of total monthly precipitation collected from the U.S. Geological Survey precipitation-collection stationat Catoctin Mountain, Maryland, for 1982-91 .......................................................... 22

12. Statistical summary of the quantity of precipitation collected from the U.S. Geological Surveyprecipitation-collection station at Catoctin Mountain, Maryland, for 1982-91................................. 23

Contents I

TABLES (continued)

13-22. Chemical analyses of precipitation collected from the U.S. Geological Survey precipitation-collection station at Catoctin Mountain, Maryland, in:

13. 1982........................................................................................... 24

14. 1983........................................................................................... 26

15. 1984........................................................................................... 28

16. 1985........................................................................................... 30

17. 1986........................................................................................... 32

18. 1987........................................................................................... 34

19. 1988........................................................................................... 3620. 1989........................................................................................... 3821. 1990........................................................................................... 40

22. 1991........................................................................................... 4223. Statistical summary of the chemical analyses of precipitation collected from the U.S. Geological Survey

precipitation-collection station at Catoctin Mountain, Maryland, for 1982-91................................. 44

24. Annual precipitation-weighted mean concentrations of field and laboratory hyrogen ion and pH of precipitation collected from the U.S. Geological Survey precipitation-collection station at Catoctin Mountain, Maryland, for 1982-91 ............................................................................ 45

25. Annual precipitation-weighted mean concentrations of chemical constituents in precipitation collected from the U.S. Geological Survey precipitation-collection station at Catoctin Mountain, Maryland, for 1982-91........................................................................................ 46

II Contents

Data on the Quantity and Chemical Quality of Precipitation, Catoctin Mountain, North- Central Maryland, 1982-91

By Karen C. Rice, Margaret M. Kennedy, Owen P. Bricker, and Colleen A. Don nelly

ABSTRACT

This report presents data on the quantity and chemical quality of precipitation from Catoctin Mountain in Cunningham Falls State Park, near Thurmont, Maryland, collected by the U.S. Geologi cal Survey (USGS) from January 1982 through De cember 1991 at a USGS precipitation-collection station. Data on the quantity of precipitation are pre sented in tables as daily, monthly, and annual totals of precipitation, in inches. Data on the chemical quality of precipitation are presented in tables as concentrations, in microequivalents per liter. Data on the quantity and chemical quality of precipitation and statistical information about the data are summa rized in tables. Data for annual precipitation- weighted mean concentrations of constituents in precipitation are summarized in tables. Annual pre cipitation-weighted mean concentrations of selected precipitation constituents are illustrated in graphs.

the mandate. In 1990, additional funding was given to the USGS by the Maryland Department of the Environ ment and the Maryland Department of Natural Resources.

Purpose and Scope

The purpose of this report is to present data on the quantity and chemical quality of precipitation collected at the USGS precipitation-collection station at Catoctin Mountain, Maryland, from January 1982 through Decem ber 1991. Descriptions of the instrumentation and meth ods used to collect samples of precipitation and field data and descriptions of the instrumentation and methods used for laboratory analyses of the samples are included. Data for the quantity and chemical quality of precipitation, sta tistical information about the data, and precipitation- weighted mean chemical data are found in tables. The report also includes graphs showing annual precipitation- weighted mean constituent concentrations of selected data.

INTRODUCTION

This report presents data for precipitation that were collected by the U.S. Geological Survey (USGS) as part of the interagency National Acid Precipitation Assess ment Program (NAPAP), in cooperation with the Mary land Department of the Environment and the Maryland Department of Natural Resources. A mandate for NA PAP was established by Congress in 1980. A precipita tion-collection station was installed in 1981 by the USGS at Catoctin Mountain in Cunningham Falls State Park, north-central Maryland (fig. 1), to monitor the quantity and chemistry of precipitation in the area as a result of

Description of Study Area

The USGS precipitation-collection station at Catoc tin Mountain is located in the William Houck Area in Cunningham Falls State Park, 3 mi west of the town of Thurmont, in Frederick County, Md. (fig. 1). The precipi tation-collection station is situated on a raised wooden platform (6.5 ft) constructed on top of a 25-ft high water- storage tank in one of the campgrounds in the park. The water-storage tank is located at an elevation of 1,700 ft and is in the middle of a clearing, with the nearest tree canopy 25 ft from the tank.

Catoctin Precipitation Data 1

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Acknowledgments

The authors would like to thank the Maryland Department of Natural Resources for allowing the pre cipitation-collection station to be maintained on Cun- ningham Falls State Park property. Appreciation is also given to the park rangers of Cunningham Falls State Park for their assistance, by providing access to the precipitation-collection station during and follow ing inclement weather.

COLLECTION AND ANALYSIS OF DATA

Collection of data on the quantity and chemical quality of precipitation at the USGS Catoctin Moun tain precipitation-collection station began in January 1982. Although this report summarizes data collected from January 1982 through December 1991, data con tinue to be collected from the station.

Instrumentation of Precipitation-Collection Station

A Belfort1 #5-780 Series Universal Recording weighing-bucket rain gage was used to record the data on the quantity of precipitation. The data were re corded with ink on a 7-day paper chart, driven by a spring-wound chart-drive mechanism. An Aero- chem Metrics model #301 automatic-sensing wet/dry atmospheric-deposition collector, powered by a 12- volt marine wet-cell battery, was used to collect sam ples of precipitation for chemical analysis. Only wet-deposition samples were collected. The Aero- chem Metrics collector was selected for this site to be consistent with the equipment used by the National At mospheric Deposition Program (NADP) and the Na tional Trends Network (NTN) program.

Field Data-Collection Methods

Samples were collected from the precipitation- collection station on a weekly basis, usually on a Tues day at 9:00 a.m., in conformance with NADP guidelines. Collecting precipitation data on a weekly basis on Tuesday is important so that all programs that collect precipitation data are consistent and data col lected by different programs and at different localities

can be compared. If data could not be collected that day (for example if a holiday fell on a Tuesday or if in clement weather prevented access to the precipitation- collection station), the data were collected on the previous or following day, when possible.

Data on the quantity of precipitation were col lected from the site by removing the paper chart from the Belfort weighing-bucket rain gage. The Belfort weighing-bucket rain gage was serviced by adjusting the water level in the weighing bucket, adding anti freeze to prevent freezing or mineral oil to prevent evaporation (depending on the season), winding the chart-drive mechanism, and installing a new paper chart. Later, the paper chart, which held the data from the previous week, was read and the daily amounts of precipitation were recorded in tables. Two lines were recorded on the paper chart-one showed the quantity of precipitation for each day of the week and the sec ond showed the time and date that the lid opened auto matically on the Aerochem Metrics wet collector.

Wet-only precipitation-chemistry samples were collected weekly from the Aerochem Metrics collec tor, if a sufficient volume of precipitation was avail able in the bucket (equivalent to 0.2 in. of pre cipitation). The bucket was retrieved and replaced with a spare bucket that had been triple-rinsed with dis tilled water. If the quantity of precipitation collected in the bucket was too small for any measurements to be made, the sample was discarded and the bucket was replaced with a clean spare bucket. If no sample was available in the collection bucket, the empty bucket was replaced with a clean spare bucket.

If up to 2 fl. oz of precipitation sample were available, temperature-compensated measurements of specific conductance and pH of the sample were per formed in the field. A small aliquot (up to 2 fl. oz) of unfiltered sample was poured into a plastic cup. The specific conductance and pH measurements were made on this separate aliquot of sample. When a lim ited amount of precipitation sample was available, the volume of the separate aliquot of sample was only large enough to wet the conductivity cell and pH elec trode sufficiently to obtain a reading in order to pre serve an adequate amount of sample to be prepared for laboratory analyses. For some weeks, there was a suf ficient volume of sample to perform only field meas urements.

The use of trade or product names in this report is for identification purposes only and does not constitute endorsement by the U.S. Geological Survey. Field Data-Collection Methods


From January 1982 through December 1989, spe cific conductance was measured using a Labline model MC-1 Mark V temperature-compensated spe cific conductance meter. Beginning in January 1990, a YSI model #34 Conductance-Resistance meter and a model #3417 conductivity cell were used to measure specific conductance. The performance of the cell was checked with specific conductance standard solutions before use. From January 1982 through December1988. a Beckman Phi 30 pH meter with a Futura n glass combination electrode was used to measure pH of the precipitation samples. Beginning in January1989. a Beckman Phi 31 pH meter with an Orion Ross glass combination electrode was used to measure pH. The electrode was calibrated before each use with standard buffer solutions of pH 7 and 4. The calibra tion of the electrode was then checked in 1 x 10 nor mal sulfuric acid. This pH measurement is reported in the tables as "pH, field."

If a sufficient volume of precipitation sample was available after the field measurements of specific conductance and pH were made, the remaining sample was prepared for laboratory analysis. The sample was filtered through a 0.1-micron pore size cellulose nitrate filter, using positive pressure delivered by a peristaltic pump. Approximately 4 oz (125 mL) of the filtered sample was chilled to 4°C in a brown polyethylene bot tle. An additional 4 oz of sample was filtered into a white, polyethylene, nitric acid-rinsed bottle; approxi mately 0.0068 fl. oz (equivalent to 200 jlL) of Baker's Instra-Analyzed concentrated nitric acid was added to preserve the sample. The filtered samples were sent to the Geochemical Cycling of Trace Elements and Nutri ents Laboratory of the Eastern Region Branch of Re gional Research of the USGS in Reston, Va., for analysis of the major inorganic ions and the unspeciated (or total) form of aluminum and iron.

Beginning in April 1990, samples were collected for analysis of the stable isotopic ratios of deuterium/protium (8D) and oxygen-18/oxygen-16 (8 O). A 2-fl. oz unfiltered precipitation sample was decanted into a flint glass bottle with a polyseal cap. The bottle caps were covered with Parafilm to further ensure against evaporation. The samples were sent to the Iso tope Fractionation Laboratory of the Eastern Region Branch of Regional Research of the USGS in Reston, Va., for analysis.

Laboratory-Analysis Methods and Instrumentation

Filtered precipitation samples were analyzed in the Geochemical Cycling of Trace Elements and Nu trients Laboratory of the Eastern Region Branch of Regional Research of the USGS in Reston, Va., for determination of major ions and unspeciated (or to tal) aluminum and iron. Samples that had been fil tered and chilled in the field were analyzed for determination of the concentrations of dissolved am monium, dissolved chloride, dissolved nitrite, dis solved nitrate, and dissolved sulfate. Laboratory pH of these samples was determined for quality-control purposes. Samples that had been filtered and pre served with nitric acid in the field were analyzed for determination of the concentrations of dissolved cal cium, dissolved magnesium, dissolved sodium, dis solved potassium, and the unspeciated forms of dissolved aluminum and iron.

From January 1982 through January 1991, labo ratory pH was determined for samples that had equilibrated with room temperature, using a Beck man Phi 71 pH meter with an Orion Ross glass com bination electrode. In January 1991, the laboratory also began using an Orion model 920A pH meter with a Corning glass combination electrode.

Detection limits for each constituent are given in the following discussion of laboratory instrumenta tion. A detection limit the concentration that can be detected with 95- percent confidence is deter mined by statistical calculation. Because the detec tion limit depends on the signal and electronic noise of the instrument, it is a function of the whole instru ment. The computer software incorporated in the Direct Current Plasma Atomic Emission Spectro- photometer (DCP-A) instrument employed by the Geochemical Cycling of Trace Elements and Nutri ents Laboratory can calculate a detection limit for every sample analyzed. It is possible that a meas ured concentration reported in the tables is lower than the reported detection limit, because the unique combination of the signal and the noise for that sam ple made it possible for a concentration to be meas ured that was lower than the normal detection limit.

In order to determine the concentrations of dis solved ammonium, dissolved chloride, dissolved ni trite, dissolved nitrate, and dissolved sulfate, the laboratory used a Dionex 16 ion chromatograph from January 1982 through October 1987. During that time, detection limits, in microequivalents per liter, were as follows: ammonium, 2.8; chloride, 1.8; nitrite, 0.8; nitrate, 0.45; and sul-

4 Catoctin Precipitation Data

fate, 0.8. Beginning in October 1987, a Dionex 2110i ion chromatograph was used for these analyses. Detection limits for that time period remained the same as for the previous instrument. Beginning in July 1989, a Dionex 100DX ion chromatograph also was used to determine ammonium concentrations with a detection limit of 2.4 fleq/L.

During January 1982 through April 1988, the labo ratory used a Perkin-Elmer #603 Atomic Absorption Spectrophotometer (AA) to determine calcium and mag nesium concentrations, and an IL 351 AA to determine sodium and potassium concentrations. During this pe riod, detection limits, in microequivalents per liter, were as follows: calcium, 2.5; magnesium, 0.8; sodium, 0.4; and potassium, 0.64. Unspeciated dissolved aluminum and iron concentrations were not determined before May 1988. From May 1988 through May 1989, the laboratory used a Varian Spectra AA-300 for determination of cat ion concentrations. During this period, detection limits, in microequivalents per liter, were as follows: calcium, 0.5; magnesium, 0.24; sodium, 0.09; potassium, 0.77; alu minum, 3.3; and iron, 2.2. Beginning in June 1989, an ARL Spectra Span V DCP-A was used for cation-concen tration determinations. During this period, detection lim its, in microequivalents per liter, were as follows: calcium, 0.45; magnesium, 0.05; sodium, 0.13; potas sium, 0.2; aluminum, 0.22; and iron, 0.38. Beginning in May 1988, concentrations of unspeciated dissolved alumi num and iron in the precipitation samples were always be low the detection limits; therefore, no values for these cations are reported in the data tables.

Quality assurance and quality control of the labora tory analyses were continuously carried out through a se ries of approved methods, which included the analysis of standards, duplicates, blanks, and field blanks. During chemical analysis, known standard solutions were rou tinely analyzed after every fifth sample. Beginning in 1985, National Institute of Standards and Technology (NIST) standard solutions were analyzed at the beginning and end of each analysis session. Interlaboratory com parisons of analytical results were initiated in 1987.

Unfiltered precipitation samples for isotopic analy sis were analyzed in the Isotope Fractionation Laboratory of the Eastern Region Branch of Regional Research of the USGS in Reston, Va. The method described by Co- plen and others (1991) was used to determine the isotopic ratio of deuterium/protium (8D). The isotopic ratio of oxygen-18/oxygen-16(8 O) was determined according to the method described by Epstein and Mayeda (1953).

DATA ON QUANTITY OF PRECIPITATION

Data on the quantity of precipitation for the study area are presented in tables as daily and monthly totals of precipitation, in inches, for each year for the period of re cord (tables 1-10). Monthly and annual total precipita tion-quantity data are summarized in table 11. A statistical summary of the monthly and annual total quan tity data of precipitation for the period of record is shown in table 12.

The precipitation-quantity sample date is the date of the 24-hour period, from midnight to midnight, during which the reported amount of precipitation fell. Some daily amounts of precipitation had to be estimated when the equipment malfunctioned. The estimated quantities of precipitation were obtained from a nearby National Oceanic and Atmospheric Administration precipitation- collection station, in Catoctin Mountain Park.

DATA ON CHEMICAL QUALITY OF PRECIPITATION

Data on the chemical quality of precipitation from the study area are presented in tables as concentrations, in microequivalents per liter, for each year of the period of record (tables 13-22). The precipitation-chemistry sam ple date is the date the sample was collected from the field and includes all precipitation that fell after the pre vious sample-collection date. Samples for which the con centration of the constituent was below the analytical detection limit are shown as "less than" (<) the detection limit. Samples for which the constituent was not ana lyzed are designated as "n.a." in the tables. Stable-iso tope data of precipitation are expressed as the deviation (delta, 6) of the ratio measured in the sample from the standard, in units of per mille (per mil, %o).

A statistical summary of data on the chemical qual ity of precipitation for the period of record is presented in table 23. The means of the chemical data were calculated as follows: samples that were not analyzed were omitted from the calculations; for samples in which the concentra tion was below the detection limit, one-half of the detec tion limit was used in the calculations. The medians of the chemical data were determined by ranking all at tempted measurements and identifying the value at the 50th percentile (the central value of the distribution).


During a rainstorm, the chemistry of the rain is gen erally more concentrated at the beginning of the storm and becomes less concentrated as the storm continues. This means that constituent concentra tions are usually higher for smaller rainstorms (less than 0.5 in.) than for larger rainstorms (more than 1 in.). This change in concentration during a storm is the result of acids and dry particulate matter wash ing out of the atmosphere. The chemical data were precipitation-weighted to take the "washing out" ef fect into account and to be able to compare chemi cal data of precipitation from different localities. The annual precipitation-weighted mean constituent concentrations were calculated by use of the relation,

where

Cw = annual precipitation-weighted mean con stituent concentration, in microequivalents per liter;

n = number of samples for the given year;

Q = individual sample concentration, in microequivalents per liter; and

Pi = the quantity of precipitation for the weekly interval, in inches.

Annual precipitation-weighted mean field and laboratory hydrogen-ion and pH-data for the period of record are summarized in table 24. Annual precipita tion-weighted mean concentrations of chemical data of the precipitation for the period of record are summa rized in table 25. The quantity of precipitation used to make the precipitation-weighted calculations (tables 24 and 25) is smaller than the total annual quantity of precipitation (table 11), because small rainstorms oc cur each year that do not produce a sufficient quantity of precipitation for collection and chemical analysis. Selected precipitation-weighted data are presented graphically. Annual precipitation-weighted means of field hydrogen-ion concentrations are shown in figure 2. The annual precipitation-weighted mean concentra tions of the sum of base cations (calcium, magnesium, sodium, and potassium), sulfate, and nitrate are shown in figure 3.

SUMMARY OF PRECIPITATION DATA

The quantity of precipitation on Catoctin Moun tain for the period of record ranged from a minimum of 36.89 in. in 1982 to a maximum of 58.48 in. in 1984 (table 11). The mean annual quantity of precipitation for the 10-year period of record was 44.45 in., and the median quantity was 42.86 in. (table 12). The long- term mean (1931-80) for annual precipitation in the re gion was 44.09 in. (Katz and others, 1985). The mean monthly data indicated that with the exception of Janu ary, all months averaged more than 3 in. of precipita tion (table 12). The medians of the monthly data indicated that December was the month in which the least precipitation fell (1.88 in.), whereas May was the month in which the most precipitation fell (5.43 in.).

Specific conductance ranged from a minimum of 1 (iS/cm on November 2, 1987, to a maximum of 290 (iS/cm on August 6, 1991 (table 23). The mean spe cific conductance for the period of record was 40.2 S/cm, and the median was 30 |lS/cm (table 23).

Mean pH values and precipitation-weighted pH values were calculated by first converting pH to hydro gen-ion activity using the relation pH = -log [hydrogen ion (in microequivalents per liter)], then calculating the mean of hydrogen-ion activities or precipitation- weighting hydrogen-ion activities, and finally convert ing back to pH. Field pH ranged from a minimum of 2.96 on June 21, 1988, to a maximum of 5.17 on Octo ber 1, 1985 (table 23). The mean field pH for the pe riod of record was 4.07, and the median was 4.18 (table 23). Precipitation-weighted mean field pH for the period of record was 4.16 (table 24). Laboratory pH ranged from a minimum of 3.5 on August 11, 1987, to a maximum of 5.96 on February 24, 1987 (ta ble 23). The mean laboratory pH for the period of re cord was 4.25, and the median was 4.37 (table 23). Precipitation-weighted mean laboratory pH for the pe riod of record was 4.34 (table 24).

Calcium concentrations ranged from a minimum of 0.05 (ieq/L on April 22, 1982, to a maximum of 92.8 |4,eq/L on October 2, 1990 (table 23). The mean calcium concentration for the period of record was 11.3 (ieq/L, and the median was 9.11 (ieq/L (table 23). The precipitation-weighted mean calcium concentra tion for the period of record was 9.06 (ieq/L (table 25).


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Magnesium concentrations ranged from a mini mum of 0.03 (Xeq/L on March 10, 1983, to a maximum of 208 ^leq/L on December 23, 1991 (table 23). The mean magnesium concentration for the period of re cord was 3.66 |J,eq/L, and the median was 2.08 |J,eq/L (table 23). The precipitation-weighted mean magne sium concentration for the period of record was 2.64 jaeq/L (table 25).

Sodium concentrations ranged from a minimum of 0.1 |j,eq/L on December 10, 1991, to a maximum of 62.9 (Xeq/L on November 26, 1982 (table 23). The mean sodium concentration for the period of record was 6.49 |j,eq/L, and the median was 4.26 |ieq/L (table 23). The precipitation-weighted mean sodium concen tration for the period of record was 6.87 (Xeq/L (table 25).

Potassium concentrations ranged from a mini mum of 0.08 |J,eq/L on August 20, 1991 and December 17, 1991, to a maximum of 25.8 |j,eq/L on August 19, 1987 (table 23). The mean potassium concentration for the period of record was 2.54 jaeq/L, and the me dian was 1.36 |j,eq/L (table 23). The precipitation- weighted mean potassium concentration for the period of record was 1.99 |J,eq/L (table 25).

Ammonium concentrations ranged from a mini mum of 0.76 |j,eq/L on January 25, 1984, to a maxi mum of 105 jaeq/L on May 13, 1982 (table 23). The mean ammonium concentration for the period of re cord was 17.9 |J,eq/L, and the median was 13.6 jaeq/L (table 23). A precipitation-weighted mean ammonium concentration was not calculated because of the small amount of data available.

Chloride concentrations ranged from a mini mum of 1.05 |J,eq/L on June 13, 1989, to a maximum of 174 ^leq/L on December 23, 1991 (table 23). The mean chloride concentration for the period of record was 13.0 |j,eq/L, and the median was 9.49 |j,eq/L (table 23). The precipitation-weighted mean chloride concen tration for the period of record was 11.11 |j,eq/L (table 25).

Nitrite concentrations ranged from a minimum of 0.1 jaeq/L on June 15, 1982 and October 28, 1982, to a maximum of 9.4 |0,eq/L on August 11, 1982 (table 23). The mean nitrite concentration for the period of record was 0.54 |j,eq/L, and the median was 0.4 |j,eq/L (table

23). A precipitation-weighted mean nitrite concentra tion was not calculated because of the small amount of data available.

Nitrate concentrations ranged from a minimum of 4.2 (Xeq/L on December 2, 1982, to a maximum of 123 |ieq/L on August 5, 1986 (table 23). The mean ni trate concentration for the period of record was 28.3 |j,eq/L, and the median was 23.7 |j,eq/L (table 23). The precipitation-weighted mean nitrate concentration for the period of record was 23.24 |j,eq/L (table 25).

Sulfate concentrations ranged from a minimum of 4.9 |j,eq/L on October 28, 1982, to a maximum of 322 |ieq/L on August 5, 1986 (table 23). The mean sulfate concentration for the period of record was 62.6 |j,eq/L, and the median was 47.8 |j,eq/L (table 23). The precipitation-weighted mean sulfate concentration for the period of record was 52.73 |J,eq/L (table 25).

6 ranged from a minimum of -120.5 per mil on October 22, 1991, to a maximum of +4.5 per mil on July 23, 1991 (table 23). The mean 6 D for the period of record was -43.1 per mil, and the median was -38.5 per mil (table 23). A precipitation-weighted mean 8 D for the period of record was not calculated because data have been collected only since April 1990. The precipitation-weighted mean 6 D for 1991 was -47.89 per mil (table 25).

1 R6 O ranged from a minimum of -16.1 per mil

on October 22, 1991, to a maximum of -0.8 per mil on July 23, 1991 (table 23). The mean 618O for the pe riod of record was -7.62 per mil, and the median was - 7.1 per mil (table 23). A precipitation-weighted mean 8 O for the period of record was not calculated be cause data have been collected only since April 1990. The precipitation-weighted mean 8 O for 1991 was - 8.03 per mil (table 25).


SELECTED REFERENCES

Bricker, O.P., and Rice, K.C., 1989, Acidic deposition to streams A geology-based method predicts their sensitivity: Environmental Science and Technol ogy, v. 23, no. 4, p.379-385.

Coplen, T.B., Wildman, J.D., and Chen, Julie, 1991, Im provements in the gaseous hydrogen-water equili bration technique for hydrogen isotope ratio analysis: Analytical Chemistry, v. 63, no. 9, p. 910-912.

Epstein, Samuel, and Mayeda, T.K., 1953, Variation of I Q

6 O content of waters from natural sources: Geo- chimica et Cosmochimica Acta, v. 4, no. 5, p. 213- 224.

Katz, E.G., Bricker, O.P., and Kennedy, M.M., 1985, Geochemical mass-balance relationships for se lected ions in precipitation and stream water, Ca- toctin Mountains, Maryland: American Journal of Science, v. 285, December, p. 931-962.

Rice, K.C., and Bricker, O.P., 1992a, Acid rain and its ef fect on streamwater quality on Catoctin Mountain, Maryland: U.S. Geological Survey Open-File Re port 92-168, Water Fact Sheet, 2 p.

. 1992b, Acid-rain induced changes in streamwater qual ity during storms on Catoctin Mountain, Mary land: U.S. Geological Survey Open-File Report 92-649, Water Fact Sheet, 2 p.


\i

TABLES 1-25


Table 1.-Quantity of daily precipitation collected from the U.S. Geological Survey precipitation-collection stationat Catoctin Mountain, Maryland, in 1982

[All values reported in inches]

Day

12345

678910

1112131415

1617181920

2122232425

262728293031

Total

January

10.84ÔO».04

.00

.00

.00

.00

.00

.05

.37

.00

.00

.42

.03

.00

.05

.00

.00

.02

.02

.18

.18

.55

.00

.04

.00

.01

.00

.00

.00

.07

X2.87

February

0.00.22.79.00.00

.00

.00

.00

.20

.00

.00

.00

.14

.00

.00

.14

.65

.06

.49

.11

.02

.00

.00

.00

.00

.00

.00

.00--~~

2.82

March

0.00.05.00.01.00

.00

.89

.01

.00

.00

.35

.00

.06

.00

.00

.80

.01

.00

.08

.19

.03

.00

.00

.00

.01

.10

.00

.00

.00

.00

.35

2.94

April

0.00.00

1.47.00.05

.47

.00

.00

.22

.00

.00

.00

.05

.00

.00

.00

.60

.00

.00

.01

.01

.00

.00

.00

.00

1.03.55.00.00.00

4.46

May

0.00.00.00.00.00

.00

.00

.20

.00

.00

.00

.00

.00

.00

.00

.00

.48

.00

.00

.02

.00

.17

.18

.03

.01

.01

.05

.30

.08

.62

.00

2.15

June

0.21.00.52.06

1.57

.00

.00

.00

.00

.35

.15

.671.90.05.00

1.09.58.00.00.00

.00

.00

.00

.00

.00

.00

.00

.00

.05

.04

7.24

July

0.00.00.56.00.00

.00

.00

.10

.00

.00

.03

.00

.00

.00

.00

.00

.00

.00

.55

.25

.00

.00

.00

.00

.00

.002.55

.08

.00

.05

.00

4.17

August

0.00.03.00.40.00

.00

.00

.00

.05

.00

.17

.00

.00

.00

.00

.00

.19

.00

.00

.00

.00

.00

.00

.08

.02

.00

.00

.00

.00

.00

.00

.94

September

0.10.00.00.00.00

.00

.00

.06

.00

.00

.00

.00

.00

.00

.03

.02

.00

.00

.00

.30

.00

.42

.01

.00

.00

1.101.19.00.00.00~

3.23

October

0.00.00.00.00.00

.00

.00

.00

.00

.00

.00

.00

.65

.00

.00

.00

.00

.00

.00

.14

.01

.00

.00

.00

.73

.02

.00.00.00.00.00

1.55

November

0.00.00.00.90.00

.00

.00

.00

.00

.00

.00

.50

.00

.00

.00

.00

.00

.00

.05

.02

.00

.11

.01

.07

.00

.00

.001.15.22.00--

3.03

December

0.19.00.00.00.00

.00

.00

.00

.00

.00

.00

.13

.00

.00

.09

.62

.00

.00

.04

.02

.00

.00

.14

.01

.00

.07

.13

.05

.00

.00

.00

1.49

Estimated value.


Table 2.--Quantity of daily precipitation collected from the U.S. Geological Survey precipitation-collection stationat Catoctin Mountain, Maryland, in 1983


Day

12345

678910

1112131415

1617181920

2122232425

262728293031

Total

January

0.00.00.00.00.04

.00

.00

.00

.05

.95

.00

.00

.00

.00

.28

.00

.02

.00

.00

.00

.00

.08

.58

.00

.01

.01

.00

.00

.00

.16

.00

2.18

February

0.001.51.26.00.00

.11

.09

.00

.00

.00

1.06.04.00.00.00

.00

.00

.00

.00

.00

.00

.00

.03

.00

.04

.00

.00

.00

.01----

3.15

March

0.06.04.00.00.00

.44

.36

.80

.20

.06

.01

.00

.00

.01

.00

.00

.022.41

.63

.00

.46

.00

.04

.00

.00

.00

.85

.00

.00

.00

.00

6.39

April

0.001.40.15.00.00

.01

.14

.551.10.97

.12

.00

.00

.101.61

.01

.03

.00

.00

.03

.00

.00

.452.23

.04

.00

.00

.00

.00

.00~

8.94

May

0.00.00.27.08.02

.00

.00

.40

.00

.00

.00

.00

.00

.07

.53

1.32.08.00.61.00

.49

.64

.01

.00

.00

.68

.00

.00

.27

.00

.02

5.49

June

0.00.03.25

1.43.00

.00

.00

.00

.00

.00

.00

.00

.00

.00

.00

.00

.181.32.08.96

.01

.00

.00

.00

.00

.00

.00

.27

.08

.00--

4.61

July

0.00.00.00.00.14

.00

.00

.00

.00

.00

.00

.00

.00

.00

.00

.00

.00

.00

.001.23

.00

.00

.10

.00

.00

.00

.00

.00

.00

.00

.00

1.47

August

0.56.01.39.02.45

.00

.00

.00

.00

.00

.63

.00

.00

.00

.00

.00

.00

.14

.00

.00

.00

.00

.00

.00

.00

.00

.00

.00U5.00

!.50

'2.85

September

0.00.00.00.00.00

.00

.00

.00

.00

.00

.00

.50

.45

.00

.00

.00

.00

.00

.00

.00

1.26.00.00.00.00

.00

.00

.00

.00

.70~

2.91

October

0.05.00.00.00.15

.00

.00

.00

.00

.05

.602.641.46.00.00

.00

.00

.05

.08

.30

.02

.262.10

.20

.39

.01

.00

.00

.00

.00

.00

8.36

November

0.00.00.10.00.06

.04

.00

.00

.001.24

.61

.00

.00

.00

.30

.00

.00

.00

.001.00

.00

.00

.00

.70

.42

.00

.00

.65

.00

.00--

5.12

December

0.00.05.00.80.00

.65

.00

.00

.00

.00

.001.471.39.00.00

.00

.00

.00

.00

.00

.061.21.00.00.00

.00

.00

.69

.02

.00

.00

6.34

Estimated value.




Day

12345

678910

1112131415

1617181920

2122232425

262728293031

Total

January

0.23.00.00

^00^00

.00

.00

.00

.00

.40

.00

.00

.06

.04

.00

.05

.00

.27

.03

.00

.00

.00

.00

.48

.00

.00

.00

.00

.00

.10

.00

l l.66

February

0.00.00.07.08.15

.02

.00

.00

.00

.15

.31

.01

.644.66

.49

.00

.07

.03

.02

.03

.00

.001.20.10.67

.00

.03

.55

.00~~

9.28

March

0.00.00.00.00.42

.00

.00

.22

.02

.00

.00

.00

.51

.06

.00

.00

.00

.00

.00

.03

1.14.00.00.00.15

.13

.081.601.21.00.00

5.57

April

0.00.00.00

1.25.30

.00

.00

.00

.00

.00

.00

.00

.00

.82

.40

.58

.25

.00

.00

.00

.00

.64

.06

.07

.00

.00

.00

.21

.00

.09

4.67

May

0.04.00

1.74.03.00

.15

.191.67.00.00

.00

.10

.05

.00

.00

.00

.00

.00

.10

.00

.01

.701.25.00.00

.00

.00

.321.29.09.00

7.73

June

0.00.00.00.00.00

.00

.00

.00

.00

.00

.13

.00

.00

.00

.00

.05

.59

.61

.01

.00

.00

.00

.05

.92

.05

.00

.00

.00

.15

.15~

2.71

July

0.35.00.00.00.25

2.48.02.00.00.12

.10

.00

.00

.00

.00

.00

.00

.25

.00

.00

1.03.09.00.00.00

.00

.90

.00

.00

.00.00

5.59

August

0.00.08.87.00.20

.00

.00

.00

.305.93

.87

.601.51.14.00

.00

.00

.00

.79

.00

.00

.00

.85

.00

.00

.00

.00

.00

.00

.00

.00

12.14

September

0.00.00.32.26.00

.00

.00

.00

.00

.00

.00

.00

.00

.05

.12

.00

.00

.00

.00

.00

.00

.00

.00

.00

.00

.04

.06

.44

.02

.19~

1.50

October

0.58.02.00.00.00

.00

.00

.00

.00

.00

.00

.00

.00

.00

.00

.00

.00

.00

.07

.01

.00

.90

.27

.15

.00

.00

.00

.52

.05

.02

.00

2.59

November

0.00.00.00.40.09

.00

.00

.00

.00

.05

.00

.00

.00

.00

.00

.00

.00

.04

.37

.02

.00

.00

.00

.00

.00

.00

.00

.501.01.70

3.18

December

0.01.02.26.00.00

.26

.00

.26

.09

.02

.02

.00

.05

.00

.00

.04

.00

.00

.21

.00

.45

.00

.00

.12

.00

.00

.00

.00

.00

.03

.02

1.86

Estimated value.


Table 4.--Quantity of daily precipitation collected from U.S. Geological Survey precipitation-collection stationat Catoctin Mountain, Maryland, in 1985


Day

12345

678910

1112131415

1617181920

2122232425

262728293031

Total

January

0.05.58.00.12.10

.00

.05

.00

.00

.07

.00

.00^06^08.00

.00

.13

.02

.05

.00

.00

.00

.00

.02

.12

.01

.00

.00

.02

.00

.30

l i.n

February

0.50.34.01.00.26

.04

.00

.02

.00

.00

.001.58.00.00.00

.00

.00

.00

.00

.00

.00

.00

.00

.00

.00

.11

.00

.00 ~--

2.86

March

0.00.00.00.08.00

.00

.03

.05

.00

.00

.36

.06

.00

.00

.00

.00

.00

.00

.00

.00

.00

.101.25.37.02

.00

.00

.00

.45

.50

.35

3.62

April

0.03.00.00.00.00

.00

.00

.00

.10

.00

.00

.00

.05

.00

.00

.05

.00

.00

.00

.00

.00

.00

.00

.00

.05

.00

.00

.00

.00

.00~

.28

May

0.001.37.40.00.00

.00

.00

.00

.00

.00

.00

.55

.00

.00

.05

.37

.86

.12

.00

.00

.28

.00

.72

.00

.00

.00

.00

.20

.00

.00

.45

5.37

June

0.05.00.00.00

1.25

.00

.09

.01

.00

.00

.00

.00

.00

.00

.28

.22

.00

.02

.00

.00

.00

.04

.26

.00

.00

.00

.00

.03

.00

.00~

2.25

July

0.09.05.00.00.00

.53

.00

.03

.14

.03

.00

.32

.00

.00

.30

.00

.00

.00

.05

.00

.00

.00

.00

.001.28

12.12'.63'.00'.00

.00

.04

'5.61

August

0.08.00.00.00.00

.00

.73

.72

.00

.00

.00

.00

.00

.20

.00

.00

.00

.14

.00

.03

.67

.00

.00

.63

.19

1.08.00.00.00.03.00

4.50

September

0.00.00.00.00

^00

'.00l .OOl .OO!.74

^00

'.00

.00

.00

.00

.00

.00

.00

.00

.00

.00

.00

.00

.35

.00

.00

.231.14.00.00.00~

'2.46

October

0.00.55.02.16.18

.00

.00

.00

.00

.00

.00

.00

.00

.10

.08

.00

.00

.00

.00

.41

1 IM'.57

.30

.25

.00

.00

.00

.00

.00

.00

.00

^.90

November

0.04.10

1.69'2.42H.52

l .io^00.00.00.00

.10

.05

.00

.26

.00

.77

.00

.00

.00

.00

.001.22^00! .oo1 .15

1 .15

.20

.89

.00

.26~

*9.92

December

0.401 .02'.00'.00

^00

'.35'.00'.00'.00'.00

.00

.00

.70

.00

.00

.00

.00

.00

.00

.00

.00

.00

.01

.03

.00

.00

.00

.00

.00

.00

.00

'1.51

Estimated value.




Day

12345

678910

1112131415

1617181920

2122232425

262728293031

Total

January

0.00.00.00.00.00

.03

.02

.01

.00

.00

.00

.00

.00

.00

.00

.00

.00

.00

.51'.14

IQO

.00

.00

.00

.03

.26

.01

.00

.00l .OO'.00

^.Ol

February

ty.OO^00^00'.75l .OO

.03

.00

.00

.10

.00

.00

.00

.00

.00

.00

.09'.19

Uo.30

'.05

'.10

^30^00^20

.02

.04

.04

.03__ ~

>3,4

March

0.01.01.00.00.00

.00

.00

.00

.00

.00

.51

.02

.541.40.23

.00

.02

.00

.00

.00

.00

.00

.00

.00

.00

.00

.00

.00

.00

.00

.00

2.74

April

0.00.00.00.00.21

.16

.00

.00

.00

.00

.06

.00

.00

.001.55

.21

.50

.00

.00

.00

.02

.28

.00

.00

.00

.00

.00

.00

.03

.00~

3.02

May

0.00.00.00.00.00

.00^00.00.03.00

.00

.00

.00

.12

.00

.54

.00

.00

.031.80

.36

.00

.06

.00

.00

.00

.08

.00

.00

.00

.00

3.02

June

0.00.00.00.00.00

3.36.25.00.00.00

.00

.00

.00

.00

.00

.00

.23

.00

.00

.20

.00

.00

.00

.72

.00

.00

.03

.00

.00

.00~

4.79

July

0.00.67.00.00.00

.00

.00

.00

.39

.00

.00

.00

.06

.00

.00

.00

.00

.00

.38

.37

.00

.00

.00

.04

.00

.00

.00

.00

.00

.00

.00

1.91

August

0.00.11.50.00.00

.62

.18

.00

.00

.00

.00

.00

.00

.00

.00

.00

.13

.00

.00

.16

.73

.00

.00

.03

.00

.00

.24

.28

.00

.00

.00

2.98

September

0.03.32.33.07.00

.00

.00

.00

.00

.00

.00

.00

.00

.00

.00

.00

.00

.03

.00

.00

.00

.00

.00

.15

.00

.00

.00

.00

.00

.00~

.93

October

1.01.00.04.50.00

.00

.00

.00

.00

.00

.00

.00

.23

.34

.00

.00

.00

.00

.00

.00

.00

.00

.00

.00

.06

.45

.00

.00

.00

.00

.00

2.63

November

0.15.26.00.09.98

.00

.42

.06

.11

.00

\90.00.00.00.00

.00

.00

.90

.00

.93

.00

.00

.06

.13

.00

.52

.00

.00

.00

.00~

'5.51

December

0.001.79.00.00.00

.00

.00

.36

.56

.02

.21

.00

.00j.ool .oo

'.oo.00.81.00.00

.00

.00

.001.55.00

.00

.00

.00^00^00l -°°

15.30

Estimated value.


Table 6.-Quantity of daily precipitation, in inches, at the USGS Catoctin Mountain precipitation-collection stationat Catoctin Mountain, Maryland, 1987


Day

12345

678910

1112131415

1617181920

2122232425

262728293031

Total

January

J0.46^32J .oo^00^00

J .ooJ .oo^00'.OO

^.20

J .oo'.00'.00

.00

.08

.00

.00

.05

.80J .09

^00'1.03'.20

^00'.03

'.20'.00! .oo.01.05.00

J7.52

February

^.00'.00

^00.00.00

.00

.00

.00'.00

^00

.00

.10

.00

.00

.00

.00

.00

.00

.00

.00

.00

.56

.24

.00

.00

.00

.00

.84~--~

! 1.74

March

0.29.00.00.00.00

.00

.00

.00

.00

.00

.00

.00

.00

.00

.00

.00

.00

.00

.00

.00

.00

.00

.00

.00

.18

.00

.00

.07

.00

.56

.87

1.97

April

0.00.26.79

2.38.64

.15

.25

.00

.00

.00

.00

.10

.00

.00

.05

.83

.62

.00

.00

.00

.00

.00

.00

.09

.00

.00

.00

.00

.00

.00~

6.16

May

0.00.05.31.74.00

.00

.00

.04

.00

.00

.00

.21

.00

.00

.02

.00

.00

.13

.37

.85

.08

.00

.45

.00

.00

.00

.00

.00

.00

.00

.00

3.25

June

0.09.00.10.09.00

.00

.03

.00

.25

.00

.00

.13

.96

.00

.00

.00

.00

.00

.00

.26

.00

.06

.00

.04

.00

.55

.00

.00

.00

.00~

2.56

July

0.20.56.00.10.00

.22

.83

.00

.00

.00

.30

.18

.10

.75

.00

.00

.00

.00

.00

.00

.00

.00

.00

.00

.00

.03

.00

.00

.00

.00

.00

3.27

August September

0.00.00.00.00.41

.00

.00

.00

.00

.00

.00

.00

.00

.00

.00

.00

.00

.00

.14

.00

.00

.70

.00

.00

.00

.14

.00

.03

.00

.00

.03

1.45

0.00.00.00.00.04

.77

.091.99.00.00

.14

.51

.14

.00

.00

.001.79.00.15.23

.00

.04

.00

.00

.00

.00

.00

.00

.00

.40~

6.29

October

0.00.00.23.00.00

.59

.00

.00

.00

.00

.04

.00

.00

.00

.00

.00

.00

.00

.00

.12

.08

.00

.00

.00

.00

.001.30.00.00.00.00

2.36

November

0.00.00.00.00.00

! .00

^00^00! .03

Us

U4! .00

^00^00! .00

^00^081 39'.03

.51

.00

.00

.00

.00

.00

.00

.21

.332.15

.00~

4.65

December

0.00.00.00.08.00

.00

.00

.00

.00

.00

.00

.00

.00

.00

.65

.00

.00

.00

.25

.18

.00

.00

.00

.00

.40

.18

.00

.00

.00

.00

.16

1.90

Estimated value.


Table 7.~Quantity of daily precipitation collected from the U.S. Geological Survey precipitation-collection stationat Catoctin Mountain, Maryland, in 1988


Day

12345

678910

1112131415

1617181920

21

22232425

262728293031

Total

January

0.09.00.00.00.00

.00

.00

.00

.00

.00

.00

.18

.00

.00

.00

.00

.29

.05

.40

.80

.00

.00

.00

.00

.04

.00

.00

.00

.00

.00

.00

1.85

February

0.05.28.00.25.00

.00

.00

.00

.00

.00

.00

.08

.00

.15

.45

.00

.00

.00

.40

.00

.00

.00

.00

.00

.00

.00

.00

.00

.00 ~

1.66

March

0.00.00.21.64.00

.00

.00

.00

.00

.00

.00

.00

.08

.00

.00

.00

.00

.01

.00

.00

.00

.00

.00

.00

.00

.65

.00

.00

.00

.00

.00

1.59

April

0.00.00.05.03

^00

^001 ll'.15

^03^00

^00^00.00.00.05

.00

.00

.38

.00

.00

l .OO

^001 .07*.22l -°°

\00.48.00.00.00

>2.,7

May

0.00.00.00.07

1.53

1.12.00.00.05.06

.00

.00

.00

.00

.00

.24

.01*2.39J4.65'.21

1 SJ

^00'.01'.65

.36

.00

.00

.00

.00

.00

.00

M..92

June

0.00.02.05.00.00

.00

.00

.06

.45

.00

.00

.00

.00

.00

.00

.06

.00

.00

.00

.00

.00

.00

.00

.00

.00

.00

.00

.00

.00

.00

.64

July

0.00.00.00.00.00

.00

.00

.00

.04

.03

.47

.46

.00

.00

.00

.00

.051.19.04.72

.10

.00

.41

.00

.00

.00

.00

.00

.00

.20

.00

3.71

August

0.00.00.00.00.00

.12

.00

.00

.00

.00

.00

.00

.00

.00

.00

.00

.23

.00

.25

.86

.03

.001.29.00.00

.00

.00

.08

.59

.00

.00

3.45

September

0.00.00.00

1.28.04

.00

.00

.00

.00

.00

.00

.00

.20

.00

.00

.00

.37

.02

.00

.06

.00

.00

.00

.75

.17

.00

.00

.00

.00

.00~

2.89

October

0.00.13.02.00.00

.00

.00

.00

.00

.00

.06

.00

.00

.00

.00

.00

.00

.17

.00

.00

1.05

.00

.00

.17

.00

.00

.00

.00

.00

.00

.00

1.60

November

0.03.00.00.20

1.23

.03

.00

.00

.00

.00

.00

.00

.47

.00

.00

.00

.25

.00

.581.42

.00

.00

.00

.00

.00

.00

.39

.00

.00

.00~

4.60

December

0.00.00.00.00.00

.00

.00

.00

.00

.00

.00

.00

.08

.05

.00

.00

.00

.00

.00

.00

.22

.00

.24

.61

.00

.00

.00

.15

.00

.00

.00

1.35

Estimated value.


Table 8.~Quantity of daily precipitation collected from the U.S. Geological Survey precipitation-collection stationat Catoctin Mountain, Maryland, in 1989


Day

12345

678910

1112131415

1617181920

2122232425

262728293031

Total

January

0.00.25.00.00.00

.00

.00

.90

.00

.00

.00

.52

.00

.00

.57

.00

.00

.00

.00

.00

.00

.00

.00

.00

.00

.20

.00

.00

.00

.17

.00

2.61

February

0.00.00.60.00.03

.06

.00

.00

.00

.00

.00

.00

.401 .291 .25

'.13'.00*.oo^00^00

l .2S

.34

.00

.00

.00

.03

.00

.00 --

12.41

March

0.00.00.00.08.30

.31

.00

.00

.00

.00

.00

.00

.00

.00

.00

.00

.00

.75

.00

.15

.10

.00

.111.01.05

.00

.00

.00

.06

.25

.24

3.41

April

0.00.10.15.05.10

.06

.00

.08

.09

.00

.00

.00

.00

.00

.31

.04

.00

.15

.05

.00

.00

.00

.00

.00

.00

.00

.00

.00

.20

.04~

1.42

May

1.64.30.00.00

2.10

.91

.00

.00

.661.22

.14

.00

.00

.391.01

.00

.00

.00

.00

.04

.00

.00

.21

.36

.00

.17

.19

.00

.00

.00

.00

9.34

June

0.00.00.19.11.00

.24

.16

.001.73.00

.00

.00

.06

.15

.51

.35

.26

.00

.00

.15

.05

.36

.54

.00

.01

.00

.66

.07

.00

.00

5.60

July

0.00.00.00

1.89.85

.15

.05

.00

.00

.00

.00

.00

.60

.07

.00

.23

.00

.00

.09

.51

.00

.00

.00

.00

.00

.00

.00

.00

.00

.89

.15

5.48

August

0.00.00.00.00.00

.06

.08

.00

.00

.00

.00

.06

.00

.00

.00

.03

.00

.00

.24

.00

.16

.15

.02

.00

.00

.00

.00

.00

.00

.25

.00

1.05

September

0.00.00.00.00.10

.00

.00

.00

.00

.00

.00

.00

.00

.00

.00

.65

.01

.00

.20

.20

.00

.60

.09

.00

.15

.35

.00

.00

.00

.00~

2.35

October

0.92.81.02.00.00

.00

.00

.00

.00

.05

.00

.00

.00

.00

.00

.00

.50

.701.09.92

.00

.00

.00

.00

.00

.00

.00

.00

.00

.00

.16

5.17

November

0.00.00.00.00.00

.05

.00

.40

.25

.00

.00

.00

.00

.00

.04

.86

.00

.00

.00

.00

.09

.00

.00

.00

.14

.10

.10

.09

.00

.00~

2.12

December

0.00.00.00.00.00

.00

.00

.00

.00

.09

.15

.00

.00

.00

.00

.00

.00

.00

.00

.00

.00

.00

.00

.00

.25

.00

.05

.00

.00

.001.11

1.65

Estimated value.




Day

12345

678910

1112131415

1617181920

2122232425

262728293031

Total

January

0.00.00.00.07.00

.00

.00

.00

.23

.00

.00

.00

.00

.00

.04

.00

.00

.00

.00

.26

.24

.00

.00

.00

.70

.23

.21

.001.53.00.00

3.51

February

0.00.00.37.10.00

.00

.00

.00

.13

.57

.00

.00

.00

.00

.02

.00^00^00^00.00

.00

.01

.65

.00

.00

.00

.10

.00

H.95

March

0.00.00.00.00.00

.00

.00

.00

.10

.00

.00

.00

.00

.00

.00

.05

.75

.00

.14

.00

.15

.00

.00

.00

.17

.00

.00

.00

.05

.26

.11

1.78

April

0.14.94.00.07.00

.07

.40

.00

.00^08

^00^00^00^20Uo

^00Us.00.00.00

.02

.00

.00

.00

.00

.00

.00

.00

.46

.20--

3,3

May

0.01.00.08.75.10

.00

.00

.00

.002.10

.00

.00

.55

.00

.00

.84

.03

.00

.00

.07

.12

.04

.00

.00

.00

1.45.03.16

1.31.00.00

7.64

June

0.00.11.05.00.00

.00

.10

.31

.20

.00

.00

.00

.00

.00

.00

.00

.001.37.05

1 .02

iQO

l '.02

UsUs!.00

^00.00.00.15.35~

.3.0,

July

0.05.00.00.00.97

.00

.00

.00

.00

.00

.571.24.20.95

'.40

.00

.00

.00

.00

.24

.39

.12

.00

.00

.00

.00

.00

.00

.00

.01

.00

5,4

August

0.00.00.00.05.33

.88

.04

.00

.17

.06

.10

.00

.66

.00

.00

.00

.00

.00

.461.45

.161.65.29.03.00

.00

.00

.00

.00

.00

.00

6.33

September

0.00.00.00.00.00

.00

.00

.00

.00

.00

.00

.00

.25

.02

.00

.39

.00

.00

.33

.00

.00

.75

.00

.00

.00

.01

.00

.00

.00

.03~

1.78

October

0.00.00.00.10.00

.00

.00

.00

.00

.22

1.65.10

H.35.09.00

.00

.001.03.00.00

.00

.102.40

.29

.00

.00

.00

.00

.00

.00

.00

*7.33

November

0.00.00.00.00.47

.00

.00l .ffJl ffl

\94

.00

.00

.00

.00

.00

.00

.18

.00

.00

.00

.00

.00

.20

.00

.00

.00

.00

.00

.00

.00~

H.93

December

0.00.00

1.17.45.00

.00

.00

.00

.00

.00

.00

.00

.00

.00

.80

.00

.10

.55

.17

.02

.33

.01

.36'.37

^00

^00^00^ss^00^00*.24

15.40

Estimated value.




Day

12345

678910

1112131415

1617181920

2122232425

262728293031

Total

January

^.00^00

.00

.00

.03

.31

.02

.00

.15

.00

.15

.66

.00

.15

.00

.88

.00

.00

.00

.00

.15

.00

.00

.00

.00

.00

.00

.00

.00

.30

.00

^.80

February

0.00.00.00.00.00

.50

.11

.00

.00

.00

.00Vool .Q31 .59

1.00

'.001.00l .n1 .19

.00

.00

.00

.00

.00

.00

.00

.00

.00

H.59

March

0.00.34.45.99.00

.23

.00

.00

.00

.00

.00

.00

.00

.00

.40

.00

.00

.56

.00

.00

.04

.161.25.00.00

.07

.21

.00

.19

.22

.00

5.11

April

0.03.00.00.00.15

.00

.00

.00

.20

.00

.00

.00*30

\2\U9

i.OO

.00

.00

.15

.15

.75

.00

.00

.10

.00

.00

.00

.00

.06

.00

2,9

May

0.01.00.02.00.10

1.05Voo^00\\2l .OO

i.oo^00!.12

^02.00

.00

.85

.00

.05

.00

.00

.00

.00

.00

.00

.00

.00

.04

.00

.04

.00

12A2

June

0.00.00.00.00.00

.00

.00

.00

.00

.00

.00

.00

.00

.00

.00

.77

.004.47

.05

.00

.00

.00

.20

.00

.00

.00

.00

.00

.00

.00

12A9

July

0.00.80.00.08.10

.00

.00

.00

.00

.00

.00

.20

.47

.00

.00

.00

.00

.00

.00

.00

.00

.05

.03

.00

.00

.70

.00

.00

.22

.00

.00

2.65

August

0.00.00.00.04.00

.00

.03

.00

.97l .OO

1.00^00^00.00.00

.00

.00

.10

.201.24

.00

.00

.00

.00

.18

.00

.00

.00

.00

.00

.00

*2.76

September

0.00.00.00

1.85.08

.10

.00

.00

.00

.05

.00

.00

.00

.20

.00

.00

.002.68

.35

.00

.00

.00

.05

.05

.36

.00

.00

.00

.00

.00

5.77

October

0.00.00.00.00.73

.65

.00

.00

.00

.00

.37

.00

.00

.00

.17

.00

.50

.00

.00

.00

.00

.00

.00^00l -°°

^00^00

^00^00.00.00

'2.42

November

0.00.00.00.00.00

.00

.00

.00

.00

.45

.13

.10

.00

.00

.00

.00

.00

.00

.00

.00

.441.50.00.00.00

.00

.00

.00

.00^08

12.70

December

10.35^.SS

*.15

.00

.00

.00

.00

.00

.76

.00

.00

.00

.23

.09

.00

.00

.00

.00

.00

.00

.00

.00

.15

.00

.00

.00

.00

.41

.65

.00

.00

M.67

Estimated value.


Tabl

e 1 l

.--Q

uant

ity o

f tot

al m

onth

ly p

reci

pita

tion

colle

cted

from

the

U.S

. Geo

logi

cal S

urve

y pr

ecip

itatio

n-co

llect

ion

stat

ion

at C

atoc

tinM

ount

ain,

Mar

ylan

d, fo

r 19

82-9

1

[All

valu

es re

porte

d in

inch

es. T

his

tabl

e in

clud

es e

stim

ated

val

ues

from

tabl

es 1

-10]

toctin

Precipitation Data

Mon

th

Janu

ary

Febr

uary

Mar

ch

Apr

il

May

June

July

Aug

ust

Sep

tem

ber

Oct

ober

Nov

embe

r

Dec

embe

r

1982

2.87

2.82

2.9

4

4.4

6

2.1

5

7.2

4

4.1

7

.94

3.2

3

1.55

3.0

3

1.49

1983

2.1

8

3.1

4

6.3

9

8.9

4

5.4

9

4.61

1.47

2.8

5

2.91

8.3

6

5.1

2

6.3

4

J^

1984

1.6

6

9.2

8

5.5

7

4.6

7

7.7

3

2.71

5.5

9

12.1

4

1.50

2.5

9

3.1

8

1.86

1985

1.78

2.8

6

3.6

2

.28

5.3

7

2.2

5

5.61

4.5

0

2.4

6

3.9

0

9.9

2

1.51

1986

1.01

3.3

4

2.7

4

3.0

2

3.0

2

4.7

9

1.91

2.9

8

.93

2.6

3

5.51

5.3

0

1987

7.52

1.74

1.97

6.1

6

3.2

5

2.5

6

3.2

7

1.45

6.2

9

2.3

6

4.6

5

1.90

1988

1.85

1.66

1.59

2.1

7

11.9

2

.64

3.71

3.4

5

2.8

9

1.60

4.6

0

1.35

1989

2.61

2.41

3.41

1.42

9.3

4

5.6

0

5.4

8

1.05

2.3

5

5.1

7

2.1

2

1.65

1990

3.51

1.95

1.78

3.1

3

7.64

3.01

5.14

6.33

1.78

7.33

1.93

5.40

1991

2.8

0

1.59

5.11

2.5

9

2.4

2

2.4

9

2.6

5

2.7

6

5.7

7

2.4

2

2.7

0

4.6

7

TO

TA

L3

6.8

957.8

058.4

84

4.0

63

7.1

843.1

23

7.4

342

.61

48.9

33

7.9

7

Tabl

e 12

.~St

atis

tical

sum

mar

y of

the

quan

tity

of pr

ecip

itatio

n co

llect

ed fr

om th

e U

.S. G

eolo

gica

l Sur

vey

prec

ipita

tion-

colle

ctio

n st

atio

n at

Cat

octin

Mou

ntai

n, M

aryl

and,

for

198

2-91

[Thi

s tab

le in

clud

es e

stim

ated

val

ues

from

tabl

es 1

-10]

3

TJ 3 o 5'

Mon

th

Janu

ary

Feb

ruar

y

Mar

ch

Apr

il

May

June

July

Aug

ust

Sep

tem

ber

Oct

ober

Nov

embe

r

Dec

embe

r

Pre

cipi

tatio

n, i

n in

ches

Min

imum 1.01

1.59

1.59 .2

8

2.15 .6

4

1.47 .9

4

.93

1.55

1.93

1.35

Yea

r

1986

1991

1988

1985

1982

1988

1983

1982

1986

1982

1990

1988

Max

imum 7.52

9.28

6.39

8.94

11.9

2

7.24

5.61

12.1

4

6.29

8.36

9.92

6.34

Yea

r

1987

1984

1983

1983

1988

1982

1985

1984

1987

1983

1985

1983

Mea

n

2.78

3.08

3.51

3.68

5.83

3.59

3.90

3.84

3.01

3.79

4.28

3.15

Med

ian

2.40

2.62

3.18

3.08

5.43

2.86

3.94

2.92

2.68

2.61

3.89

1.88

AN

NU

ALT

OT

AL

36.8

9 19

8258

.48

1984

44.4

542

.86

Table 13.~Chemical analyses of precipitation collected from the U.S. Geological Survey precipitation-collection

[H.S/cm, microsiemens per centimeter, psq/L, microequivalents per liter, n.a., not analyzed; <, less than]

Specific pH, Hydrogen pH, Hydrogen conduct- field ion, labora- ion, lab- Calcium, Magnesium,

Date ance (standard field tory (stan- oratory dissolved dissolved (uS/cm) units) (ueq/L) dard units) (ueq/L) (ueq/L) (ueq/L)

01/15/8201/22/8201/28/8202/04/8202/1 1/82

02/18/8202/25/8203/04/8203/11/8203/18/82

03/25/8204/01/8204/07/8204/10/8204/16/82

04/22/8204/29/8205/13/8205/20/8205/27/82

06/02/8206/08/8206/15/8206/17/8206/24/82

07/01/8207/08/8207/14/8207/21/8207/28/82

08/04/8208/11/8208/18/8208/25/8209/08/82

09/22/8209/29/8210/14/8210/21/8210/28/82

11/04/8211/12/8211/19/8211/26/8212/02/8212/20/8212/31/82

1330211620

7925

1022224

47272115

103

1513

1214965

2529251739

6539

1015687

12265

15377

172

6316364030

55142672121629

4.43.94.24.34.2

3.84.253.724.254.25

3.964.24.254.263.8

4.54.453.654.14

4.23.9544.154

3.63.93.43.83.6

3.63.83.43.73.4

3.94.574.274.025.04

3.934.64.333.924.584.444.18

39.81125.89

63.150.1263.1

158.4956.23

190.5556.2356.23

109.6563.156.2354.95

158.49

31.6235.48

223.8779.43

100

63.1112.210070.79

100

251.19125.89398.11158.49251.19

251.19158.49398.11199.53398.11

125.8926.9253.795.59.12

117.4925.1246.77

120.2326.336.3166.07

4.754.34.384.494.38

3.974.333.754.394.5

4.534.554.684.85n.a.

4.734.643.84.18n.a.

4.394.394.354.544.09

3.934.223.794.563.83

3.683.913.563.933.51

3.964.554.31n.a.

5.93

4.324.954.594.14.934.684.15

17.7850.1241.6932.3641.69

107.1546.77

177.8340.7431.62

29.5128.1820.8914.13

n.a.

18.6222.91

158.4966.07

n.a.

40.7440.7444.6728.8481.28

117.4960.26

162.1827.54

147.91

208.93123.03275.42117.49309.03

109.6528.1848.98

n.a.1.17

47.8611.2225.779.4311.7520.8970.79

24.513177.497.98

117.98

<2.55.999.48

18.924.7<2.5<2.5

n.a.

.053.66

25.434.4

n.a.

6.4910.53.494.497.49

<2.54.8

<2.516.517

29.414.932.445.2<2.5

<2.5<2.510.9

n.a.4.2

11.55.99

12186.999.48

16.5

0.92.472.221.973.87

4.444.9<.8

.745.42

2.966.74<.8<.8n.a.

2.38.57

8.148.14n.a.

1.561.561.23

.991.81

<.81.97<.82.92.6

5.672.386.835.67<.8

1.41.072.1n.a.

2.4

5.763.292.5<.8

.8

.824.9


station at Catoctin Mountain, Maryland, in 1982

Sodium, Potassium, Ammonium, Chloride, Nitrite, Nitrate, Sulfate, dissolved dissolved dissolved dissolved dissolved dissolved dissolved (ueq/L) (ueq/L) (ueq/L) (peq/L) (ueq/L) (ueq/L) (ueq/L)

20.74.5

14.66.712.31

6.162.126.6748.26

4.86.9

34.58.1n.a.

35.82.837.92.1n.a.

4.93.2

11.52.56

3.139.5

6.74.86n.a.

4.491.78

14.15.8

10.7

34.27.7n.a.

8.9

11.24.6

10.862.9

3.810.916.1

2.733.658.185.453.05

2.12<.647.68

12.5<.64

6.73.12.31n.a.

2.4<.648.9<.64

n.a.

<.64<.64<.64<.64<.64

2.61.442.74.46n.a.

4.821.99<.642.6

10.7

<.641.86.4n.a.

17.9

5.85.14.72.31.11.54.4

26.217.29.12

10.3<2.8

9.87.33

<2.86.66

15.6

15.816.3<2.8

3.2n.a.

<2.88.37

10579

n.a.

29.823.1

8.615.69.4

18.59.2

20.723.2

n.a.

31.925.131.119.738.8

16.89.9

26n.a.

4

9.611.813.949.5

2.94.38.5

2.857.876.168.14

14.5

5.477.019.273.854.13

4.911.99.98.1n.a.

22.81316.410.7

n.a.

5.76.7

10.38.89.6

9.76.7

25.111

n.a.

22.88.4

19.117.645.8

5.54.2

12.5n.a.

18.8

31.211.132.856.523.721.929.4

<0.8<.8<.8<.8<.8

<.8<.8<.8<.8<.8

1.3.8

<.8<.8n.a.

<.8<.8<.85.8n.a.

<.8<.8

.1<.8

.9

1.5<.8<.8

.95n.a.

<.89.4<.85.5<.8

.9

.21.3n.a..1

2.7<.8<.8<.85.14.2<.8

11.45141.241.246.6

49.223.313.810.722.9

41.136.617.915.3n.a.

14.313.8

11459

n.a.

26.126.716.47.9

24.3

47.724.552.928.6

n.a.

79.331.1

10234.263.2

36.91127.6

n.a.<.45

22.95.7

19.753.5

4.210.518.4

36.234.273.244.220.6

26.438

1693337.4

69.846.439.411.4n.a.

31.424.2

230104

n.a.

26.449.645.832.875.8

10778.2

13088.8n.a.

192114238126138

82.21430.9n.a.4.9

54.29.5

3611210.910.854

Date

01/15/8201/22/8201/28/8202/04/8202/11/82

02/18/8202/25/8203/04/8203/11/8203/18/82

03/25/8204/01/8204/07/8204/10/8204/16/82

04/22/8204/29/8205/13/8205/20/8205/27/82

06/02/8206/08/8206/15/8206/17/8206/24/82

07/01/8207/08/8207/14/8207/21/8207/28/82

08/04/8208/11/8208/18/8208/25/8209/08/82

09/22/8209/29/8210/14/8210/21/8210/28/82

11/04/8211/12/8211/19/8211/26/8212/02/8212/20/8212/31/82



[|O.S/cm, microsiemens per centimeter; jieq/L, microequivalents per liter; n.a., not analyzed; <, less than]



01/06/8301/13/8301/20/8301/27/8302/03/83

02/10/8302/17/8303/03/8303/10/8303/24/83

03/31/8304/07/8304/14/8304/21/8304/28/83

05/05/8305/12/8305/19/8305/26/8306/02/83

06/09/8306/23/8306/30/8307/07/8307/21/83

07/28/8308/05/8308/11/8308/18/8309/01/83

09/15/8309/22/8310/06/8310/13/8310/20/83

10/27/8311/03/8311/09/8311/16/8311/23/83

12/01/8312/08/8312/15/83

4328311427

5680594518

2735222522

4352162952

393968

144114

21561

10870

124

6726181922

1527382014

2317

7

4.284.264.234.534.25

4.223.763.984.024.43

4.354.214.284.294.44

4.194.024.424.223.89

4.114.033.843.493.67

3.433.913.733.963.7

4.134.34.064.53.84

4.464.374.13.584.43

4.314.354.87

52.4854.9558.8829.5156.23

60.26173.78104.71

95.537.15

44.6761.6652.4851.2936.31

64.5795.538.0260.26

128.82

77.6293.33

144.54323.59213.8

371.54123.03186.21109.65199.53

74.1350.1287.131.62

144.54

34.6742.6679.43

263.0337.15

48.9844.6713.49

n.a.4.41n.a.n.a.

4.16

n.a.3.9n.a.

4.244.62

4.364.24.424.354.48

4.164.114.714.464.09

4.24.193.913.843.62

n.a.4.13.853.853.64

4.054.684.514.764.58

4.8n.a.n.a.

4.635.07

4.54.545.23

n.a.38.9

n.a.n.a.

69.18

n.a.125.89

n.a.57.5423.99

43.6563.138.0244.6733.11

69.1877.6219.534.6781.28

63.164.57

123.03144.54239.88

n.a.79.43

141.25141.25229.09

89.1320.8930.917.3826.3

15.85n.a.n.a.

23.448.51

31.6228.84

5.89

n.a.8.98n.a.

10.63.99

n.a.31.4

n.a.1911

19.59.486.99

116.99

31.918.5111919.5

9.989.48

17.528.923.5

n.a.13.524.516.725

30.93.61

1413.513.5

7.49n.a.n.a.

6.499.98

5.9912.52.99

n.a.<0.8

n.a.<.8

.8

n.a.5.76n.a..03

<.8

7.46.585.764.113.29

10.75.761.644.934.93

1.641.643.297.44.11

n.a.3.624.933.628.39

6.581.374.939.053.29

2.47n.a.n.a..82

6.58

1.652.471.65



Sodium, Potassium, Ammonium, Chloride, Nitrite, Nitrate, Sulfate, dissolved dissolved dissolved dissolved dissolved dissolved dissolved

(ueq/L) (ueq/L) (ueq/L) (ueq/L) (ueq/L) (ueq/L) (ueq/L)

n.a.16.6

n.a.10.69.57

n.a.8.27n.a.

6.136.18

5.398.052.26

16.55.22

10.94.263.488.73.48

3.914.393.059.132.61

n.a.3.913.04

10.910.4

5.653.11

11.7305.65

5.22n.a.n.a.

3.0423.6

3.044.395.65

n.a.3.2n.a.

5.8.75

n.a.1.75n.a.

2.16.58

1.66.83.5.75.42

41.41

.752.33

.83

.75

.75

.25

.58

.66

n.a..65.76

2.762.91

1.92.64

2.79.75.58

.33n.a.n.a..49.75

.581.16

.39

n.a.11.6

n.a.11.7

n.a.

n.a.n.a.n.a.n.a.n.a.







n.a.n.a.n.a.

n.a. n.a.28.8 <0.8

n.a. n.a.17.8 2.927.4 <.8

n.a. n.a.25.1 <.8

n.a. n.a.10.7 <.88.33 <.8

6.08 <.814 <.87.63 <.8

17.4 <.86.02 <.8

16.6 <.811.2 <.84.24 <.8

13.3 <.810.9 <.8

8.28 <.817.2 <.817.6 <.849.3 <.854.4 <.8

n.a. n.a.28.3 <.845.2 <.829.7 <.824.8 <.8

20.2 <.86.34 <.8

11.1 <.832 <.813.5 <.8

10.7 <.8n.a. n.a.n.a. n.a.

15 <.840.5 <.8

11.9 <.814.8 <.814.1 <.8

n.a.22.4

n.a.14.313.9

n.a.84.8

n.a.48.218.5

25.130.31826.89.9

177.68

15.731.461.6

12.425.929.730.638.1

n.a.24.968.247.277.4

15.45.497.697.8

23.6

16.9n.a.n.a.

32.85

21.525.34.4

n.a.41.8

n.a.30.428.3

n.a.109

n.a.59.936.4

57.155.834.152.940

99673457.2

102

8066.872.498.3

135

n.a.69.9

178156226

11427.338.424.433.6

22.6n.a.n.a.

31.923.2

37.731.613.1

Date

01/06/8301/13/8301/20/8301/27/8302/03/83

02/10/8302/17/8303/03/8303/1 0/8303/24/83

03/31/8304/07/8304/14/8304/21/8304/28/83

05/05/8305/12/8305/19/8305/26/8306/02/83

06/09/8306/23/8306/30/8307/07/8307/21/83

07/28/8308/05/8308/11/8308/18/8309/01/83

09/15/8309/22/8310/06/8310/13/8310/20/83

10/27/8311/03/8311/09/8311/16/8311/23/83

12/01/8312/08/8312/15/83


Table 15.-Chemical analyses of precipitation collected from the U.S. Geological Survey precipitation-collection

[jiS/cm, microsiemens per centimeter; jieq/L, microequivalents per liter; n.a., not analyzed; <, less than]


Date ance (standard field tory (stan- oratory dissolved dissolved (uS/cm) units) (Hecl/L) dard units) (ueq/L) (ueq/L) (ueq/L)

01/05/8401/16/8401/25/8402/07/8402/15/84

02/21/8402/28/8403/06/8403/27/8404/03/84

04/10/8404/1 7/8404/24/8405/01/8405/08/84

05/15/8405/22/8405/30/8406/12/8406/19/84

06/26/8407/03/8407/10/8407/17/8407/24/84

07/31/8408/07/8408/14/8408/21/8408/28/84

09/05/8409/18/8410/03/8410/23/8410/30/84

11/06/8411/13/8411/20/841 2/04/8412/12/8412/24/8412/31/84

718222014

3325483843

4134386526

30122

199845

2339128016

5038405533

4576141017

14241715153916

4.774.494.424.34.62

4.114.4944.064.05

4.084.134.073.914.18

4.253.74.383.794

4.314.124.633.94.14

3.853.684.13.964.09

3.963.774.454.564.26

4.464.124.44

4.664.474.084.35

16.9832.3638.0250.1223.99

77.6232.36

10087.189.13

83.1874.13

85.11123.0366.07

56.23199.5341.69

162.18100

48.9875.8623.44

125.8972.44

141.25208.9379.43

109.6581.28

109.65169.8235.4827.5454.95

34.6775.8636.3121.8833.8883.1844.67

4.984.654.54n.a.

5.04

4.334.54.23

4.254.15

4.274.394.324.274.45

4.61n.a.

4.86n.a.

4.05

4.374.074.78n.a.

4.56

4.024.154.154.034.22

4.15n.a.

4.874.994.54

4.83n.a.

4.64.934.754.21n.a.

10.4722.3928.84

n.a.9.12

46.7731.6258.8856.2370.79

53.740.74

47.8653.735.48

24.55n.a.

13.8n.a.

89.13

42.6685.1116.6

n.a.27.54

95.570.7970.7993.3360.26

70.79n.a.

13.4910.2328.84

14.79n.a.

25.1211.7517.7861.66

n.a.

9.2711.814

n.a.6.18

11.36.18

15.47.21

17.5

22161357.98.98

26n.a.

19.115.18.66

6.9313.514.3

n.a.15.6

14.613.513.519.319.3

20.6n.a.

11.4128.33

5.56n.a.

1310.26.48

13n.a.

<0.84.95.1n.a.

3.21

3.212.628.862.933.06

3.421.582.5

10.11.18

7.88n.a.

5.25.59

.99

1.231.662.18n.a..24

1.921.791.321.421.42

1.68n.a.

1.93.17.12

.44n.a..15.54.9.19n.a.



Sodium, Potassium, Ammonium, Chloride, Nitrite, Nitrate, Sulfate, dissolved dissolved dissolved dissolved dissolved dissolved dissolved (ueq/L) (ueq/L) (ueq/L) (ueq/L) (ueq/L) (ueq/L) (ueq/L)

2.7415.515.8

n.a.22.6

4.75.44

33.97.24.12

5.593.222.54

10.213.8

13.7n.a.

157.323.76

3.377.575.13n.a.

10.8

13.24.13

12.33.053.27

5.54n.a.

4.413.311.9

19.2n.a.

1.8315.11113.7

n.a.

0.651.62

.76n.a..68

.59

.884.98

.91.13

2.381.131.135.841.13

10.7n.a.

5.653.382.15

1.591.431.85n.a.

2.14

1.711.431.081.971.25

1.82n.a.

1.44.82.96

.56n.a..8

2.46.82.85n.a.

n.a.n.a.0.76n.a.n.a.







n.a.n.a.n.a.n.a.n.a.n.a.n.a.

7.9319.722

n.a.32.9

1212.11511.59.63

15.32.389.398.022.86

4.48n.a.

6.3327.62.81

44.956.83n.a.

3.34

6.754.184.455.82.82

2.71n.a.

6.498.536.34

20.9n.a.

3.5319.210.58.61n.a.

1.72 8.692.96 27.5<.8 17.5n.a. n.a.

<.8 13.1

<.8 15.7<.8 18.9<.8 33<.8 18.3<.8 22.2

<.8 26.1<.8 25.71.33 12.2<.8 73.3<.8 23

<.8 32.5n.a. n.a.

<.8 19.6<.8 35.2<.8 30.5

<.8 19.7<.8 22.2<.8 11.3n.a. n.a.

<.8 14.4

<.8 29.4<.8 26.6<.8 28.4<.8 27.6<.8 22.7

<.8 24.8n.a. n.a.

<.8 11<.8 11<.8 17.6

<.8 12.9n.a. n.a.

<.8 35.8<.8 13.6<.8 22.6<.8 46.9n.a. n.a.

17.829.439.1

n.a.29.2

42.245.181.162.870.8

93.353.660.4

15258

95.4n.a.

4692.2

103

51.577.128.4

n.a.39.5

1328581.8

12783.6

97.5n.a.

2520.231.1

23.9n.a.

17.624.923.469.4

n.a.

Date

01/05/8401/16/8401/25/8402/07/8402/15/84

02/21/8402/28/8403/06/8403/27/8404/03/84

04/10/8404/17/8404/24/8405/01/8405/08/84

05/15/8405/22/8405/30/8406/12/8406/19/84

06/26/8407/03/8407/10/8407/17/8407/24/84

07/31/8408/07/8408/14/8408/21/8408/28/84

09/05/8409/18/8410/03/8410/23/8410/30/84

11/06/8411/13/8411/20/8412/04/8412/12/8412/24/8412/31/84



(jiS/cm, microsiemens per centimeter, jieq/L, microequivalents per liter; n.a., not analyzed; <, less than]

Specific pH, Hydrogen pH, Hydrogen conduct- field ton, labora- ton, lab- Calcium, Magnesium,


01/08/8501/15/8501/22/8501/29/8502/05/85

02/13/8502/27/8503/05/8503/12/8503/26/85

04/02/8504/09/8504/16/8504/23/8504/30/85

05/08/8505/14/8505/21/8505/28/8506/05/85

06/11/8506/18/8506/25/8507/02/8507/11/85

07/16/8507/23/8507/30/8508/06/8508/13/85

08/20/8508/27/8509/05/8509/1 1/8509/26/85

10/01/8510/08/8510/15/8510/23/8510/31/85

11/06/8511/12/8511/21/8512/02/8512/10/8512/17/85

141518

n.a.13

1632813117

2941

n.a.44

n.a.

2110193431

4230283625

26n.a.

795

9

7732

n.a.5534

431571828

n.a.4133211125

4.474.374.44.344.55

4.44.14.034.214.38

4.194.184.13.984.25

4.274.74.324.124.22

3.874.024.113.984.23

4.183.454.513.694.46

3.913.993.353.94.07

5.174.213.714.684.41

n.a.3.964.194.44.84.09

33.8842.6639.8145.7128.18

39.8179.4393.3361.6641.69

64.5766.0779.43

104.7156.23

53.719.9547.8675.8660.26

134.995.577.62

104.7158.88

66.07354.81

30.9204.1734.67

123.03102.33446.68125.8985.11

6.7661.66

194.9820.8938.9

n.a.109.6564.5739.8115.8581.28

4.7n.a.n.a.n.a.

4.89

4.57n.a.n.a.

4.34.51

4.37n.a.n.a.n.a.n.a.

4.345.114.414.314.25

4.024.194.18n.a.

4.3

4.26n.a.

4.65n.a.

4.85

3.934.15n.a.

4.014.18

5.854.28n.a.

4.82n.a.

5.15n.a.

4.244.35n.a.

4.33

19.95n.a.n.a.n.a.

12.88

26.92n.a.n.a.

50.1230.9

42.66n.a.n.a.n.a.n.a.

45.717.76

38.948.9856.23

95.564.5766.07

n.a.50.12

54.95n.a.

22.39n.a.

14.13

117.4970.79

n.a.97.7266.07

1.4152.48

n.a.15.14

n.a.

7.08n.a.

57.5444.67

n.a.46.77

4.54n.a.n.a.n.a.

3.79

10.6n.a.n.a.

12.17.2


4.546.327.98

11.87.32

3.999.48

12n.a.

11.8

8.48n.a.

9.19n.a.

7.88

27.66.57n.a.

19.77.88

.814.9n.a.

9n.a.

4.1n.a.

2.44<2.5

n.a.2.44

1.88n.a.n.a.n.a.

1.52

2.89n.a.n.a.

4.631.01


2.641.891.231.811.27

2.846.297.4n.a.

13

5.8n.a..99

n.a..99

4.67.85

n.a.2.414.1

.132.53n.a.

11.5n.a.

6.3n.a.

1.1.7

n.a..53




4n.a.n.a.n.a.

2.62

12.7n.a.n.a.

4.841.52


4.142.352.761.522.62

2.491.662.9n.a.

1.66

2.07n.a.

1.11n.a.

3.04

3.732.11n.a.

2.7610.4

2.612.8n.a.

28.1n.a.

30.3n.a.

4.613.4n.a.

2.4

1.3n.a.n.a.n.a.

1.06

5.17n.a.n.a.

2.24.94


2.211.62

.35

.811.39

.981.11

.81n.a.

1.97

1.04n.a.

1.48n.a.

2.21

7.013.69n.a.

1.852.21

1.489.6n.a.

4.06n.a.

11.1n.a..72.72

n.a.1.5









n.a.n.a.n.a.n.a.n.a.n.a.

4.84n.a.n.a.n.a.

3.08

11.8n.a.n.a.

5.583.41


6.24.974.924.545.16

5.337.38

10n.a.

6.13

5.48n.a.

4.23n.a.

4.23

16.93.34n.a.

6.2620.3

1.675n.a.

28n.a.

28.6n.a.

5.134.79n.a.

2.05

<0.8n.a.n.a.n.a.

<.8

<.8n.a.n.a.

<.8<.8

<.8n.a.n.a.n.a.n.a.

<.8<.81.88<.8<.8

<.8<.8<.8

n.a.<.8

<.8n.a.

<.8n.a.

<.8

<.8<.8n.a.

<.8<.8

<.8<.8

n.a.<.8n.a.

<.8n.a..98.5

n.a.1

14.5n.a.n.a.n.a.

16.9

13.2n.a.n.a

31.317.5

24n.a.n.a.n.a.n.a.

29.8122036.121.8

35.226.330

n.a.25.5

22.2n.a.

15.8n.a.

11.2

47.523

n.a.27.120.8

13.325.2

n.a.17.8

n.a.

9.54n.a.

23.613.6

n.a21

32.2n.a.n.an.a

17.1

30.5n.a.n.a.

56.535.3

64.4n.an.a.n.a.n.a.

56.315.342.577.559.3

88.875.669

n.a74.8

67.2n.a

36.4n.a.

24.7

16764.7

n.a.47.126.5

16.556.5

n.a37.8

n.a.

20.7n.a.

53.235.9

n.a.35.5

Date

01/08/8501/15/8501/22/8501/29/8502/05/85

02/13/8502/27/8503/05/8503/12/8503/26/85

04/02/8504/09/8504/16/8504/23/8504/30/85

05/08/8505/14/8505/21/8505/28/8506/05/85

06/11/8506/18/8506/25/8507/02/8507/11/85

07/16/8507/23/8507/30/8508/06/8508/13/85

08/20/8508/27/8509/05/8509/11/8509/26/85

10/01/8510/08/8510/15/8510/23/8510/31/85

11/06/8511/12/8511/21/8512/02/8512/10/8512/17/85



[US/cm, microsiemens per centimeter, n.eq/L, microequivalents per liter; n.a., not analyzed; <, less than]


Date ance (standard field tory (stan- oratory dissolved dissolved (uS/cm) units) (peq/L) dard units) (ueq/L) (ueq/L) (ueq/L)

01/08/8601/21/8601/28/8602/05/8602/10/86

02/18/8602/24/8603/05/8603/11/8603/18/86

04/09/8604/15/8604/24/8604/29/8605/21/86

05/28/8606/10/8606/17/8606/24/8607/08/86

07/15/8607/22/8607/28/8608/05/8608/12/86

08/19/8608/26/8609/04/8609/23/8609/30/86

10/07/8610/14/8610/28/8611/03/8611/12/86

11/25/8612/02/8612/08/8612/16/861 2/23/8612/30/86

n.a.201726

n.a.

2240243022

8868215218

5333

1166933

4772

15415445

3614257334

246

178

21

42179

3496

9

3.634.274.284.263.84

4.133.944.264.54.31

3.934.024.413.964.26

4.313.993.743.94.25

3.813.833.463.443.99

4.154.464.213.744.07

4.314.844.494.924.33

4.064.624.764.163.764.51

234.4253.752.4854.95

144.54

74.13114.8254.9531.6248.98

117.4995.538.9

109.6554.95

48.98102.33181.97125.8956.23

154.88147.91346.74363.08102.33

70.7934.6761.66

181.9785.11

48.9814.4532.3612.0246.77

87.123.9917.3869.18

173.7830.9

n.a.4.384.474.43n.a.

4.394.234.394.544.52

3.92n.a.

4.46n.a.

4.63

44.273.814.094.14

4.013.92n.a.

3.534.07

4.514.554.32n.a.

4.35

4.425.064.475.034.4

4.134.694.974.253.824.67

n.a.41.6933.8837.15

n.a.

40.7458.8840.7428.8430.2

120.23n.a.

34.67n.a.

23.44

10053.7

154.8881.2872.44

97.72120.23

n.a.295.12

85.11

30.928.1847.86

n.a.44.67

38.028.71

33.889.33

39.81

74.1320.4210.7256.23

151.3621.38

n.a.5.73.3

13.1n.a.

7.8813.110.515.86.57

15.9n.a.

12.3n.a.

11.1

17.211.116.414.78.03

13.420.1

n.a.34.411.1

7.376.156.15n.a.

14.9

13.11.756.13

12.36.13

16.38.154.08

10.210.210.2

n.a.4.132.131.98n.a.

1.273.111.845.94

.57

8.35n.a.

1.86n.a.

2.32

2.941.74.257.362.26

4.817.36n.a.

10.11

3.11.37.25

n.a.3.14

3.27.78.78

3.271.05

14.29

.1411.43

.57



Sodium, Potassium, Ammonium, Chloride, Nitrite, Nitrate, Sulfate, dissolved dissolved dissolved dissolved dissolved dissolved dissolved (ueq/L) (ueq/L) (ueq/L) (ueq/L) (ueq/L) (peq/L) (ueq/L)

n.a.19109.07n.a.

5.368.256.6

19.24.54

13.2n.a.

5.61n.a.

2.41

4.615.215.814.091.29

4.315.17n.a.

6.373.18

12.74.63.18n.a.

5.9

7.395.983.46

5.661.42

2.5929.3

2.2

2.859.99

3.63

n.a.2.21.51.49n.a.

1.274.257.64

1.49.64

4.23n.a.

2.35n.a.

3.76

2.12.94

2.581.78

.4

1.21.59n.a.

4.013.24

4.77

1.911.14n.a.

2.92

2.66

3.831.69

2.91.45

.78

.78

.39

.783.53

.91









n.a.18.5105.88n.a.

9.88.05

11.119.12.47

20.3n.a.

5.52n.a.

8.74

12

7.3652.8

9.9519.5

19.314.6

n.a.65.310.4

34.7

6.7510.2

n.a.24.6

4.17.958.43

82.91

10.4

2112.911.918.7

10.5

n.a. n.a.<0.8 25.9<.8 15.7<.8 26.9n.a. n.a.

<.8 22.4<.8 34.6<.8 42.1

<.8 31.1<.8 14.2

<.8 65.4n.a. n.a.

<.8 15.6n.a. n.a.

<.8 17

<.8 38.6<.8 16.1

.5 41.2<.8 43.9<.8 18.3

<.8 25.3<.8 37.2n.a. n.a.

<.8 123<.8 32.2

<.8 14.1<.8 12.6<.8 20.3n.a. n.a.

<.8 22.4

<.8 15.6<.8 7.58<.8 21.2

<.8 4.58<.8 13.9

<.8 40.3<.8 8.2<.8 8.59

<.8 32.3<.8 104<.8 11.3

n.a.33.731.343.4

n.a.

39.86419.555.832.5

130n.a.

43.1n.a.

38.8

96.453.4

12492.567.2

97135

n.a.322102

22.631.253

n.a.58.7

52.610.734.5

13.528.6

60.125.68.06

52.312130.8

Date

01/08/86

01/21/8601/28/86

02/05/8602/10/86

02/18/8602/24/8603/05/86

03/11/8603/18/86

04/09/8604/15/8604/24/8604/29/8605/21/86

05/28/86

06/10/8606/17/8606/24/8607/08/86

07/15/8607/22/8607/28/86

08/05/8608/12/86

08/19/86

08/26/8609/04/8609/23/8609/30/86

10/07/86

10/14/8610/28/86

11/03/8611/12/86

11/25/8612/02/8612/08/8612/16/861 2/23/8612/30/86



, microsiemens per centimeter; \ieq/L, microequivalents per liter; n.a., not analyzed; <, less than]



01/07/8701/13/8701/20/8701/28/8702/03/87

02/17/8702/24/8703/03/8703/31/8704/07/87

04/14/8704/21/8704/28/8705/06/8705/13/87

05/19/8705/26/8706/02/8706/09/8706/16/87

06/23/8706/30/8707/08/8707/14/8708/11/87

08/19/8708/24/8709/01/8709/08/8709/15/87

09/22/8709/30/8710/05/8710/13/8710/27/87

11/02/8711/13/8711/24/8712/01/8712/08/87

12/15/8712/22/8712/30/87

184327

849

618

142616

58312841

100

7943508332

49804446

142

894665

845

2719362335

138171125

303123

4.654.134.364.814.01

3.934.84.614.344.52

4.234.344.334.163.77

3.774.114.053.843.95

4.043.814.124.063.49

3.814.073.984.984.04

4.454.434.224.354.11

5.044.144.584.854.39

4.484.324.28

22.3974.1343.6515.4997.72

117.4915.8524.5545.7130.2

58.8845.7146.7769.18

169.82

169.8277.6289.13

144.54112.2

91.2154.8875.8687.1

323.59

154.8885.11

104.7110.4791.2

35.4837.1560.2644.6777.62

9.1272.4426.314.1340.74

33.1147.8652.48

4.664.194.854.38n.a.

n.a.5.964.874.614.77

4.244.614.654.363.81

3.874.184.063.833.92

43.774.124.193.5

3.84.044.015.034.01

4.34.514.324.484.45

5.164.384.74.884.62

4.374.364.58

21.8864.5714.1341.69

n.a.

n.a.1.1

13.4924.5516.98

57.5424.5522.3943.65

154.88

134.966.0787.1

147.91120.23

100169.8275.8664.57

316.23

158.4991.297.72

9.3397.72

50.1230.947.8633.1135.48

6.9241.6919.9513.1823.99

42.6643.6526.3

8.1512.212.26.11n.a.

n.a.10.24.08

1412

21.97.86

14.22.8

18.8

3.141.571.57

14.26.9

12.45.11

10.27.48

17

33.812.5222.254.04

5.476.49

15.74.79

23.2

56.486.982.5

32.4

9.98<2.5

5.48

1.571.431.29

.29n.a.

n.a..86

1.721.39

.28

1.392.531.011.523.04

1.011.014.053.83.15

2.81.892.521.652.46

7.9217.318.41.651.65

1.654.128.222.46

14

.822.464.111.655.76

5.76<.81.64




11.314.412.32.59n.a.

n.a.5.189.8

11.87.76

5.728.014.887.039.92

4.821.935.242.344.14

12.56.135.572.78

10.5

16.97.05

15.24.783.91

3.482.17

21.33.48

16.5

1.34.78

12.65.227.39

15.22.172.17

1.057.454.57

.98n.a.

n.a..78.91

4.323.85

2.023.211.193.627.24

2.591.552.072.072.18

1.121.081.21

.812.05

25.81.792.8

.511.54

1.281.79<.642.444.8

1.031.032.05

.512.02

3.593.591.03

n.a.n.a. .n.a.n.a.n.a.








n.a.n.a.n.a.

17.119.421.77.02n.a.

n.a.9.9

10.51414.5

14.119.816.47.79

23.5

12.87.5

25.119.218

20.729.711.612.929.5

52.310.751.111.610.2

10.812.2

13311.962.3

9.496.48

14.39.96

21.5

13.210.812.6

<0.8 16.8<.8 52.8<.8 25<.8 13.1n.a. n.a.

n.a. n.a.<.8 8.66<.8 6.85<.8 17.6<.8 15.6

<.8 44.5<.8 22.6<.8 11.54.1 36.4<.8 102

<.8 48.3<.8 30.9<.8 18<.8 107<.8 70.1

<.8 67.1<.8 79.2<.8 30.4<.8 36.2<.8 88.6

<.8 55.5<.8 32.1<.8 41.5<.8 4.57<.8 34.6

<.8 21.7<.8 27.3<.8 75.8<.8 24.9<.8 60.2

<.8 5.05<.8 20.4<.8 12.6<.8 8.23<.8 41.1

<.8 22<.8 15.4<.8 14.2

28.873.533.116.6

n.a.

n.a.1921.850.228.5

84.461.243.364.2

140

16210251.4

230198

12715380.891.3

306

16884.7

12427.391.1

60.138.860.133.366.6

16.235.429.814.934.8

62.246.947.3

Date

01/07/8701/13/8701/20/8701/28/8702/03/87

02/17/8702/24/8703/03/8703/31/8704/07/87

04/14/8704/21/8704/28/8705/06/8705/13/87

05/19/8705/26/8706/02/8706/09/8706/16/87

06/23/8706/30/8707/08/8707/14/8708/11/87

08/1 9/8708/24/8709/01/8709/08/8709/15/87

09/22/8709/30/8710/05/8710/13/8710/27/87

11/02/8711/13/8711/24/8712/01/8712/08/87

12/15/8712/22/8712/30/87


Table 19.--Chemical analyses of precipitation collected from the U.S. Geological Survey precipitation-collection

[jiS/cm, microsiemens per centimeter; neq/L, microequivalents per liter; n.a., not analyzed; <, less than]


Date ance (standard field tory (stan- oratory dissolved dissolved (uS/cm) units) (peq/L) dard units) (peq/L) (ueq/L) (Hecl/L)

01/12/8801/19/8801/27/8802/02/8802/09/88

02/1 6/8802/23/8803/08/8803/29/8804/05/88

04/12/8804/19/8804/26/8805/03/8805/10/88

05/17/8805/24/8805/31/8806/07/8806/1 4/88

06/21/8807/12/8807/19/8807/28/8808/02/88

08/09/8808/23/8808/30/8809/06/8809/13/88

09/19/8809/27/8810/04/8810/11/8810/18/88

10/25/8811/08/8811/15/8811/22/8811/29/8812/27/88

1014161716

1726241044

2731385229

8329459638

26877512753

3582211733

3814315723

18152718

922

4.854.574.444.64.54

4.414.34.344.674.05

4.454.134.123.884.18

3.784.083.873.733.91

2.963.43.793.863.7

3.973.444.174.253.68

3.724.224.153.834.21

4.334.584.164.334.834.2

14.1326.9236.3125.1228.84

38.950.1245.7121.3889.13

35.4874.1375.86

131.8366.07

165.9683.18

134.9186.21123.03

1096.48398.11162.18138.04199.53

107.15363.08

67.6156.23

208.93

190.5560.2670.79

147.9161.66

46.7726.369.1846.7714.7963.1

5.264.824.64.724.61

4.554.494.434.77n.a.

4.374.384.274.074.29

3.854.284.01n.a.

4.1

n.a.3.763.894.183.94

n.a.3.764.284.4n.a.

4.154.54n.a.n.a.n.a.

n.a.n.a.n.a.

4.574.944.27

5.515.1425.1219.0524.55

28.1832.3637.1516.98

n.a.

42.6641.6953.785.1151.29

141.2552.4897.72

n.a.79.43

n.a.173.78128.82

66.07114.82

n.a.173.7852.4839.81

n.a.

70.7928.84

n.a.n.a.n.a.

n.a.n.a.n.a.

26.9211.4853.7

11.517.5

4.512.59.48

13.511.17.868.36n.a.

22.86.71

1110.28.57

20.110.211.4

n.a.16.7

n.a.15.47.042.84

23.9

n.a.13.65.942.79n.a.

18.67.63n.a.n.a.

13.6

2.548.032.591.12.844.24

2.472.47

.824.112.47

1.654.441.973.13n.a.

3.465.16.257.43.46

9.212.472.39n.a.

4.11

n.a.3.71.071.326.58

n.a.2.712.31.23n.a.

1.971.32n.a.n.a.

5.76

1.073.952.96

.581.971.81




3.488.262.17

13.98.08

6.7615.35.223.48n.a.

12.26.96

22.610.410.4

15.75.223.74n.a.

2.39

n.a..96

<.092.484.48

n.a.3.873.482.17n.a.

2.74.57

n.a.n.a.

5.13

2.448.66

12.41.267.265.35

5.135.13

.778.182.81

1.5313.32.051.02n.a.

4.784.09

16.48.183.07

12.32.054.22n.a.

2.3

n.a.1.99

.66

.91.94

n.a..97.92.72

n.a.

2.23.56

n.a.n.a.

18

.951.991.25

.232.051.64









8.54 <0.810.3 <.810.1 <.818.5 <.86.31 1.1

7.32 <.813.3 <.812 <.87.13 <.8n.a. n.a.

10.6 <.89.35 <.8

14.2 <.814.2 <.811.1 <.8

29.1 <.812.5 <.811.4 .39

n.a. n.a.8 .46

n.a. n.a.12.1 <.87.08 <.86.5 <.8

15.2 <.8

n.a. n.a.9.56 <.88.58 <.86.4 <.8n.a. n.a.

6.58 <.84.38 <.8n.a. n.a.n.a. n.a.

9.13 1.62

5.21 <.813.1 <.818.7 <.83.63 <.89.97 <.8

10.4 <.8

31.613.813.5199.54

15.227.31822.9

n.a.

18.323.734.338.828.2

4.862939.2

n.a.41

n.a.40.932.22943.8

n.a.6918.414.4

n.a.

28.513.1

n.a.n.a.

14.3

20.312.211.612.98.07

28.6

35.526.231.122.934.2

35.778.74221.4

n.a.

55.562.997.55189.2

14264.279.8

n.a.72.7

n.a.15410452.8

131

n.a.157

45.4

34.9

n.a.

90.928.5

n.a.n.a.

43.6

27.533.444.326.215.952.2

Date

01/12/8801/19/8801/27/8802/02/8802/09/88

02/16/8802/23/8803/08/8803/29/8804/05/88

04/1 2/8804/19/8804/26/8805/03/8805/10/88

05/17/8805/24/8805/31/8806/07/8806/14/88

06/21/8807/12/8807/19/8807/28/8808/02/88

08/09/8808/23/8808/30/8809/06/8809/13/88

09/1 9/8809/27/881 0/04/8810/11/8810/18/88

10/25/8811/08/8811/15/8811/22/8811/29/881 2/27/88



[jiS/cm, microsiemens per centimeter; jieq/L, microequivalents per liter; n.a., not analyzed; <, less than]


Date ance (standard field ton/ (stan- oratory dissolved dissolved (uS/cm) units) (ueq/L) dard units) (ueq/L) (ueq/L) (ueq/L)

01/03/8901/10/8901/17/8901/31/8902/07/89

02/14/8902/21/8902/28/8903/09/8903/21/89

03/29/8904/04/8904/11/8904/18/8904/24/89

05/02/8905/09/8905/17/8905/23/8905/30/89

06/06/8906/13/8906/20/8906/27/8907/05/89

07/11/8907/18/8907/25/8908/01/8908/08/89

08/15/8908/22/8908/29/8909/05/8909/19/89

09/26/8910/03/8910/18/8910/24/8910/31/89

11/07/8911/14/8911/21/8911/29/89121/18/8912/27/89

1624153527

3135242120

849514843

2211295537

436

123624

3540175253

1055373627

1213131236

2017

824

n.a.15

4.44.34.434.114.26

4.244.154.254.374.42

4.663.974.014.014.06

4.314.564.213.964.09

3.994.814.534.044.24

4.114.014.363.953.91

4.883.894.014.024.32

4.614.494.524.534.19

4.424.614.824.28n.a.

4.47

39.8150.1237.1577.6254.95

57.5470.7956.2342.6638.02

21.88107.1597.7297.7287.1

48.9827.5461.66

109.6581.28

102.3315.4929.5191.257.54

77.6297.7243.65

112.2123.03

13.18128.8297.7295.547.86

24.5532.3630.229.5164.57

38.0224.5515.1452.48

n.a.33.88

4.524.374.554.24.3

4.334.254.234.364.54

4.734.094.124.094.19

4.334.644.25n.a.

4.15

4.054.754.584.14.3

4.24.084.383.974.03

n.a.3.92n.a.

4.094.33

4.624.574.544.58n.a.

4.454.44.764.44.44n.a.

30.242.6628.1863.150.12

46.7756.2358.8843.6528.84

18.6281.2875.8681.2864.57

46.7722.9156.23

n.a.70.79

89.1317.7826.379.4350.12

63.183.1841.69

107.1593.33

n.a.120.23

n.a.81.2846.77

23.9926.9228.8426.3

n.a.

35.4839.8117.3839.8136.31

n.a.

5.747.78

.63.399.33

6.491.151.45.648.43

.514.517.76.74

18.7

.45

.651.9n.a.

8.88

4.59.9

4.844.342.79

11.22.792.253.59

23.4

n.a.8.48n.a.

5.941.2

2.3.1

2.44.9

n.a.

11.24.645.497.543.99n.a.

2.061.07

.66

.992.06

1.89.91.58

1.651.81

.743.463.781.565.68

.33

.41

.66n.a.

2.22

1.23.16

1.231.4

.91

2.38.66.99.9

5.43

n.a.1.73n.a..66.58

2.06.66.66

<.05n.a.

2.8.74

1.561.971.23n.a.




4.181.87

.9113.52

3.05.3

<.093.481.13

1.2253.73.788.2

<.09<.09<.09

n.a..3

<.13<.13

.742

.91

1.74.26

1.351

11.4

n.a.2.65n.a.

1.39.26

8.13.44.7.13

n.a.

3.87.44

3.224.871.83n.a.

1.21.59

.281.251.38

.59

.51

.38

.921.02

.311.185.069.28

10.5

.514.76

.26n.a.

1.23

.74

.541.36

.84

.61

4.63.2.56.97

8.59

n.a.9.72n.a.

3.48.77

.79

.61

.64

.23n.a.

4.02.97

1.252.841.25n.a.

n.a.n.a.

10.4n.a.n.a.





19.725.410.632.518.3

n.a.27

n.a.4.92

17.9

9.4613.97.634.48n.a.

10.49.56.639.898.84n.a.

7.53 <0.87.66 .95.3 <.85.68 <.8

21 <.8

8.24 <.85.79 <.83.81 <.85.3 <.84.29 <.8

4.63 <.87.76 <.89.23 <.8

11.9 <.816.1 <.8

3.16 <.82.39 <.83.47 <.8n.a. n.a.

5.11 <.8

4.47 <.81.05 <.82.71 <.84.87 <.83.51 <.8

6.37 <.83.48 <.83.66 <.85.82 <.8

16.4 <.8

n.a. n.a.5.19 <.8n.a. n.a.

5.2 1.344.02 <.8

12.3 <.84.35 <.82.87 <.82 <.8n.a. n.a.

9.56 <.84.62 <.85.37 <.88.32 <.88.89 <.8n.a. n.a.

23.327.39.88

32.830.8

3032.424.716.816

9.159.657.233.739.2

17.29.38

24.2n.a.

36.2

29.57.14

12.847.212.3

27.232.916.345.147.2

n.a.35.5

n.a.25.728

7.0913.112.77.18n.a.

20.719.28.26

23.431.7

n.a.

32.139.324.146.447.8

33.84537.434.746.2

18.188.574.8

102102

41.819.554.9

n.a.76.8

84.912.52662.857.5

75.584.145.496.7

122

n.a.127

n.a.73.747.2

31.231.723.720.3

n.a.

40.839.51838.112.9

n.a.

Date

01/03/8901/10/8901/17/8901/31/8902/07/89

02/14/8902/21/8902/28/8903/09/8903/21/89

03/29/8904/04/8904/1 1/8904/18/8904/24/89

05/02/8905/09/8905/17/8905/23/8905/30/89

06/06/8906/13/8906/20/8906/27/8907/05/89

07/1 1/8907/18/8907/25/8908/01/8908/08/89

08/15/8908/22/8908/29/8909/05/8909/19/89

09/26/8910/03/8910/18/8910/24/8910/31/89

11/07/8911/14/8911/21/8911/29/8912/18/8912/27/89



IjiS/cm, microsiemens per centimeter; psq/L, microequivalents per liter, %o, per mil; n.a., not analyzed; <, less than]

Specific pH, Hydrogen pH, Hydrogen conduct- field ion, labora- ion, lab- Calcium, Magnesium, Sodium,

Date ance (standard field tory (stan- oratory dissolved dissolved dissolved (uS/cm) units) (ueq/L) dard units) (ueq/L) (ueq/L) (ueq/L) (ueq/L)

01/02/9001/09/9001/23/9001/30/9002/06/90

02/13/9002/20/9002/27/9003/13/9003/21/90

03/27/9004/03/9004/10/9004/17/9004/25/90

04/30/9005/08/9005/15/9005/23/9005/29/90

06/05/9006/12/9006/19/9006/26/9007/03/90

07/10/9007/17/9007/24/9007/31/9008/07/90

08/14/9008/21/9008/28/9009/18/9009/25/90

10/02/9010/09/9010/16/9010/24/9011/06/90

11/13/9011/20/9011/27/9012/04/9012/18/9012/26/90

2218262036

30143295325

46533039

111

3343752528

1259356755

4324506129

4041316341

944017

927

1430

n.a.231716

4.334.374.294.384.06

4.23.674.243.944.33

4.084.054.24.13.61

4.224.084.7644.27

4.73.884.173.814.01

4.064.283.93.794.21

4.094.113.813.834.03

3.654.084.64.724.29

4.494.124.264.34.414.83

46.7742.6651.2941.6987.1

63.1213.857.54

114.8246.77

83.1889.1363.179.43

245.47

60.2683.1817.38

10053.7

19.95131.8367.61

154.8897.72

87.152.48

125.89162.1861.66

81.2877.62

154.88147.9193.33

223.8783.1825.1219.0551.29

32.3675.8654.9550.1238.914.79

4.394.424.424.464.24

4.26n.a.

4.33n.a.

4.4

n.a.4.054.254.133.65

4.234.094.814.494.29

4.953.94.143.863.98

4.114.293.95n.a.

4.33

4.24.124.264.254.12

4.454.585.084.994.47

4.744.674.634.434.795.8

40.7438.0238.0234.6757.54

54.95n.a.

46.77n.a.

39.81

n.a.89.1356.2374.13

223.87

58.8881.2815.4932.3651.29

11.22125.8972.44

138.04104.71

77.6251.29

112.2n.a.

46.77

63.175.8654.9556.2375.86

35.4826.38.32

10.2333.88

18.221.3823.4437.1516.22

1.58

1.754.346.791.2

29.7

4.34n.a.

5.94n.a.

7.58

n.a.6.879.136.79

27.1

3.3411.22.99

302.2

12.114.510.518.911.3

182.994.99n.a.

4.49

7.093.493.29

163.19

92.849.38.632.498.98

4.9936.9243.999.48

26.4

0.821.321.23

.91.56

.99n.a.

3.21n.a.

2.88

n.a.1.811.894.525.43

1.153.041.4

18.2.58

2.222.882.224.362.88

3.621.15

.99n.a..58

1.15.49

1.44.77

.49

10.27.988.721.483.29

1.643.952.712.3

.829.46

2.783.573.092.574.78

1.35n.a.

9.18n.a.

6.96

n.a.3.481.87

13.65.7

1.042.131.174.091.04

6.092.74

.484.131.04

1.911.57

.74n.a..57

1.13<.133.962.78

.78

16.814.238.84.138.53

5.486.963.577.87

.9657



Potassium, Ammonium, Chloride, Nitrite, Nitrate, Sulfate, dissolved dissolved dissolved dissolved dissolved dissolved (ueq/L) (ueq/L) (ueq/L) (ueq/L) (Heq/L) (ueq/L)

1.282.89

21.7.2

4.96

1.1n.a.

3.3n.a.

1.13

n.a.1.21.151.258.21

1.531.462.02

21.7.79

2.431.13

.793.631.48

1.971.131.02n.a..41

.72

.31

.611.28

.59

9.0810.91.25

.612.2

.364.35

11.2.54.38

19.7

10.28.01

26.49.36

18.2

14.6n.a.

12.8n.a.

20.9

n.a.44.97.57

21.458.7

25.333.25.51

29.214.6

<2.429.42422.645.2

41.19.92

16.6n.a.

18.5

45.624.913.227.328.1

4128.16.82

<2.410.8

9.6820.96.26

11.68.24

38.7

5.498.08

26.45.758.76

3.71n.a.

14.4n.a.

8.53

n.a.5.857.01

16.821.7

46.112.946.923.52

8.296.683.899.56.69

5.285.885.14n.a.

4.21

5.413.358.79

21.82.88

1815.846.95.899.99

8.749.52

12.411.83.15

54.7

<0.8 12.1<.8 20<.8 29.7<.8 15<.8 36.2

<.8 28.2n.a. n.a.

<.8 31n.a. n.a.

<.8 28.5

n.a. n.a.<.8 53.5<.8 39.5<.8 42.3<.8 98.4

<.8 31<.8 47.2<.8 7.67<.8 36.4<.8 20.5

<.8 17.6<.8 52.8<.8 20.6<.8 58.6<.8 47.1

<.8 28.6<.8 21.8<.8 27.4

n.a. n.a.<.8 20.5

<.8 31.1<.8 30.2<.8 27.5<.8 63.8<.8 32.5

<.8 61.2<.8 29.3<.8 6.82<.8 6.69<.8 24.3

<.8 12<.8 43.8<.8 22.9<.8 18.8<.8 10.2<.8 21.8

33.630.241.528.354.9

48n.a.

37.5n.a.

40.8

n.a.86.133.868.1

246

58.286.517.687.648.3

17116

75.1138116

10841.4

108n.a.

54.8

85.973.751.993.280.6

12187.428.514.143.3

15.936.129.434.430.244.1

5 D (*)



n.a.n.a.n.a.

-46n.a.

-37-22.5-38.5-7

-49.5

-56.5-15.5-20.5-58-14

-15.5-35.5-37.5

n.a.-36

-25.5-36-37-40-31.5

n.a.n.a.

-13-26.5-4.5

-51.5-55-72-10-62.5-27.5

5 180



n.a.n.a.n.a.

-8.05n.a.

-6.45-4.75-6.8-2.4-8.1



n.a.n.a.n.a.

-7

-6.15

n.a.n.a.

-3.45-6.25-4.05

-9-9.5

-10.55-4.9

-10.15-5.1

Date

01/02/9001/09/9001/23/9001/30/9002/06/90

02/13/9002/20/9002/27/9003/13/9003/21/90

03/27/9004/03/9004/10/9004/17/9004/25/90

04/30/9005/08/9005/15/9005/23/9005/29/90

06/05/9006/12/9006/19/9006/26/9007/03/90

07/10/9007/17/9007/24/9007/31/9008/07/90

08/14/9008/21/9008/28/9009/18/9009/25/90

10/02/9010/09/9010/16/9010/24/9011/06/90

11/13/9011/20/9011/27/9012/04/9012/18/9012/26/90



QiS/cm, microsiemens per centimeter, êq/L, microequivalents per liter; %o, per mil; n.a., not analyzed; <, less than]

Specific pH, Hydrogen pH, Hydrogen conduct- field ion, labora- ion, lab- Calcium, Magnesium, Sodium,

Date ance (standard field tory (stan- oratory dissolved dissolved dissolved (uS/cm) units) (ueq/L) dard units) (ueq/L) (ueq/L) (peq/L) (peq/L)

01/02/9101/08/9101/15/9101/22/9102/05/91

02/12/9102/19/9102/26/9103/05/9103/12/91

03/19/9103/26/9104/02/9104/09/9104/16/91

04/23/9104/29/9105/07/9105/14/9105/21/91

05/28/9106/04/9106/18/9106/25/9107/09/91

07/17/9107/23/9107/30/9108/06/9108/13/91

08/20/9108/27/9109/10/9109/17/9109/24/91

10/01/9110/08/9110/15/9110/22/9111/12/91

11/19/911 1/26/9112/03/9112/10/9112/17/91

12/23/9112/30/91

620122823

6336261836

2223502328

3443207318

106138368856

2915238

29073

3868425248

3719551420

6913111720

6812

4.894.214.554.164.28

3.824.144.274.484.2

4.264.273.984.284.19

4.084.044.43.764.35

3.513.494.083.613.88

4.073.3643.173.75

3.993.613.984.273.87

4.094.373.844.554.35

3.884.624.534.414.39

4.064.57

12.8861.6628.1869.1852.48

151.3672.4453.733.1163.1

54.9553.7

104.7152.4864.57

83.1891.239.81

173.7844.67

309.03323.59

83.18245.47131.83

85.11436.52100676.08177.83

102.33245.47104.7153.7

134.9

81.2842.66

144.5428.1844.67

131.8323.9929.5138.940.74

87.126.92

5.254.65.164.565.04

4.064.384.734.894.93

4.634.634.555.514.66

4.374.444.854.134.78

n.a.n.a.

4.244.044.08

4.2n.a.

4.12n.a.

3.86

4.083.874.134.134.13

4.614.614.044.944.79

n.a.5.144.714.964.78

4.454.9

5.6225.126.92

27.549.12

87.141.6918.6212.8811.75

23.4423.4428.183.09

21.88

42.6636.3114.1374.1316.6

n.a.n.a.

57.5491.283.18

63.1n.a.

75.86n.a.

138.04

83.18134.974.1374.1374.13

24.5524.5591.211.4816.22

n.a.7.24

19.510.9616.6

35.4812.59

2.643.997.49

1117.5

7.986.49

11.513.552.9

17.514.528.939.926.4

1127.91670.417.5

n.a.n.a.

3.998.48

12

2.5n.a.

10.3n.a.

4.44

.66.042.4

12.96.1

5.13.89

10.16.044.59

n.a.11.3

1.656.894.54

13.75.99

1.152.061.354.691.56

3.952.387.242.3

11.1

1.151.43.375.023.87

2.8814.15.59

11.13.45

n.a.n.a..99

2.82.71

1.07n.a.

2.06n.a.

1.15

12.71

.72.714.2

37.42.631.896.421.4

n.a.5.81.89

16.52.4

2081.32

1.1712.789.351.44

4.09.91

5.097.135.48

1.441.173.577.134.61

7.577.392.044.311.91

n.a.n.a..74

2.612.91

.87n.a..83n.a.

1.44

3.23.35

.91.87

.96

.17<.13

.65

.221.52

n.a.2.87

.13

.1

.43

6.61<.13



Potassium, Ammonium, Chloride, Nitrite, Nitrate, Sulfate, dissolved dissolved dissolved dissolved dissolved dissolved

(ueq/L) (ueq/L) (ueq/L) (ueq/L) (ueq/L) (ueq/L)

0.49.95

1.02.64.92

1.46.56

1.2.56

3.07

.69

.561.792.3

.89

.432.11.56

12.31.13

n.a.n.a..43

1.431.02

.69n.a.

<.2n.a..28

.08

.71.31.2

.28

.56<.2<.2

.15

.66

n.a..51

<.2<.2

.08

.1<.2

5.629.986.37n.a.n.a.



n.a.n.a.n.a.n.a.

16.7




<2.4<2.4

n.a.n.a.n.a.


n.a.n.a.

3.96 <0.84.89 <.87.6 <.8

19.3 <.84.71 <.8

11.3 <.84.99 <.87.78 <.8

10.9 <.88.09 <.8

4.97 <.84.03 <.87.86 <.8

10.2 <.87.49 <.8

10.8 <.810.7 <.87.12 <.8

16.6 <.89.24 <.8

n.a. n.a.n.a. n.a.

8.04 1.0730.9 <.8

9.56 <.8

11.9 <.8n.a. n.a.

7.69 <.8n.a. n.a.

10.4 <.8

7.84 <.813.7 <.85.78 <.8

14.9 <.89.64 <.8

60.6 <.86.52 <.89.48 <.84.7 <.85.85 <.8

n.a. n.a.9.96 <.83.36 <.8

21.5 <.82.96 <.8

174 <.82.44 <.8

9.1719.213.324.421.3

74.239.921.720.648

19.621.14719.324.4

22.437.422.656.815.1

n.a.n.a.

31.966.440.2

17.6n.a.

42.4n.a.

53.1

23.766.626.344.728.5

2512.868.416.113.4

n.a.8.825.57

13.613

7.094.26

9.5630.520.341.333.6

84.541.535.226.278.4

29.435.882.737.249.8

60.27044.4

14134.4

n.a.n.a.

67.590.6113

60.7n.a.

86.2n.a.

140

83.114679.394.7

107

40.92872.530.931.3

n.a.18.617.827.526.3

8.8117.8

6 D

-94

-110.5-63.5-39.5-84.5

-14.5-103-39-47

-44.5

-65-50

-60.5-16

-28.5

-103.5-38.5-34

-32.5-45.5

-17

-19.5-29.5-39.5-26

-26.54.5

-29-6

-18.5

-52-49-36

-29.5-14.5

-45-64

-52.5-120.5-62.5

n.a.-17.5-78.5-90-73

-87-60

8 18 o

-13.45-15.1-10.6-8.05

-11.85

-4.4-15-7.4-7.1-7.2

-10.8-7.8-9.1-4.6

-6.35

-15

-6.95-6.4-4.6

-7.35

-3.2-3.5-5.6-6.3-4.7

-5.45-.8-5-1.5-4.5

-8.55-8.3

-6.85-5.4-4.4

-8.15-10.1-8.75

-16.1-10.1

n.a.-4.6

-11.35-13.1-9.8

-12-10.05

Date

01/02/9101/08/9101/15/9101/22/9102/05/91

02/12/9102/19/9102/26/9103/05/9103/12/91

03/19/9103/26/9104/02/9104/09/9104/16/91

04/23/9104/29/9105/07/9105/14/9105/21/91

05/28/9106/04/9106/18/9106/25/9107/09/91

07/17/9107/23/9107/30/9108/06/9108/13/91

08/20/9108/27/9109/10/9109/17/9109/24/91

10/01/9110/08/9110/15/9110/22/9111/12/91

11/19/9111/26/9112/03/9112/10/9112/17/91

12/23/9112/30/91


Table 23.--Statistical summary of the chemical analyses of precipitation collected from the U.S. Geological Survey precipitation-collection station at Catoctin Mountain, Maryland, for 1982-91

[All values in microequivalents per liter, except where noted; |iS/cm, microsiemens per centimeter; %o, per mil]

Physical properties and constituents

Minimum Date Maximum Date Mean Median

Specific conduct ance (uS/cm)

Field pH (standard units)

Laboratory pH (standard units)

Calcium

11/02/87 290

2.96 06/21/88

3.5 08/11/87

08/06/91

5.17 10/01/85

5.96 02/24/87

.05 04/22/82 92.8 10/02/90

40.2

4.07

4.25

11.3

30

4.18

4.37

9.11

Magnesium .03 03/10/83 208 12/23/91 3.66 2.08

Sodium .1 12/10/91 62.9 11/26/82 6.49 4.26

Potassium .08 08/20/91 12/17/91

25.8 08/19/87 2.54 1.36

Ammonium .76 01/25/84 105 05/13/82 17.9 13.6

Chloride 1.05 06/13/89 174 12/23/91 13 9.49

Nitrite .1 06/15/82 10/28/82

9.4 08/11/82 .54 .4

Nitrate

Sulfate

8 D (%<>)

8 180(%o)

4.2

4.9

-120.5

-16.1

1 2/02/82

10/28/82

10/22/91

10/22/91

123 08/05/86

322 08/05/86

4.5 07/23/91

-.8 07/23/91

28.3

62.6

-43.1

-7.62

23.7

47.8

-38.5

-7.1


Tabl

e 24

.--A

nnua

l pre

cipi

tatio

n-w

eigh

ted

mea

n co

ncen

tratio

ns o

f fie

ld a

nd la

bora

tory

hyd

roge

n io

n an

d pH

of p

reci

pita

tion

colle

cted

from

the

U.S

. Geo

logi

cal

Surv

ey p

reci

pita

tion-

colle

ctio

n st

atio

n at

Cat

octin

Mou

ntai

n, M

aryl

and,

for

198

2-91

[jieq

, mic

roeq

uiva

lent

s pe

r lite

r]

o w o

o 5'

o 3

O 5'

5T

Yea

r

1982

1983

1984

1985

1986

1987

1988

1989

1990

1991

The f

ollo

w! n

a

Qua

ntity

us

ed t

o

- p

red

pita

-tion-w

eig

ht

(inch

es)

35.9

7

55

.74

57

.57

42

.65

37

.12

42

.93

36

.94

41

.5

49

.95

37

.97

data

are

the

to

tals

FIE

Hyd

rogen

ion

(ueo

/L)

91

.68

75.8

63

.95

49

.45

72

.52

54.3

9

94

.93

50

.87

60.1

79

.06

and

orec

ic

LD

PH

(sta

ndar

dun

its) 4.04

4.1

2

4.1

9

4.3

4.1

4

4.2

6

4.0

2

4.2

9

4.2

2

4.1

litatio

n-w

eia

hte

c

Qua

ntity

us

ed t

o

- pre

cipita

tio

n-w

eig

ht

(inch

es)

32.8

6

54

.76

56

.65

40.4

1

36

.72

42.7

7

36.2

8

40

.87

49

.65

37

.7

J m

eans

for

the

10

LAB

OR

A

Hyd

rogen

ion

(uec

yL)

44

.9

48

.75

42

.14

35.7

52

.53

47

.32

58

.07

44

.86

44

.79

42

.83

-ve

ar

oeri

TO

RY PH

(sta

ndar

dun

its) 4.35

4.31

4.3

8

4.4

5

4.2

8

4.3

2

4.2

4

4.3

5

4.3

5

4.3

7

od o

f re

cord

:o o 0)

19

82

-91

43

8.3

46

8.2

64.

16428.6

74

5.9

74

.34

£ Ta

ble

25.-A

nnua

l pre

cipi

tatio

n-w

eigh

ted

mea

n co

ncen

tratio

ns o

f che

mic

al c

onst

ituen

ts in

pre

cipi

tatio

n co

llect

ed fr

om th

e U

.S. G

eolo

gica

lSu

rvey

pre

cipi

tatio

n-co

llect

ion

stat

ion

at C

atoc

tin M

ount

ain,

Mar

ylan

d, fo

r 198

2-91

D> w o 5' o

3

o 5' sr §

Yea

r i

o

1982

1983

1984

1985

1986

1987

1988

1989

1990

1991

Qua

ntity

us

ed to

-

volu

me-

C

wei

ght

(inch

es)

32.8

6

54.7

6

56.6

5

40.4

1

36.7

2

42.7

7

36.2

8

40.8

7

49.6

5

37.7

[All

va] lu

es in

mic

ro©

quiv

alen

ts p

er li

ter,

exc

ept w

here

not

ed; %

o, p

er m

il;--

, dat

a no

t col

lect

ed]

Bas

e ca

tions

( < C

alci

um

Mag

nes-

S

odiu

m

Pot

assi

um

ium

(

8.51

11.8

6

13.1

7

6.92

10.7

3

8.06

8.67

3.51

7.33

9.78

2.1

3.4

2.39

3.37

2.22

2.12

2.51

1.04

2.71

4.31

9.95

7.88

11.0

1

8.9 6.01

7.14

5.24

1.37

6.93

2.28

2.68

1.02

1.88

3.51

1.85

2.61

2.28

1.35

2.35 .7

1

Sum

of

base

C

hlor

ide

natio

ns

23.2

4

24.1

7

28.4

4

22.7

20.8

1

19.9

3

18.6

9

7.28

19.3

3

17.0

8

11.2

16.4

8

10.3

5

10.2

5

10.8

14.7

7

9.99

4.89

10.7

5

9.79

Nitr

ate

Sul

fate

6

D

818

O

(%<)

(%

<)

23.5

1

23.0

4

21.6

8

19.0

7

24.6

4

27.5

6

25.3

20 23.2

4

25.3

9

45.3

51.1

9

58.7

9

43.1

8

54.7

8

60.7

1

61.7

3

44 49.5

5

56.5

4 -4

7.8

9

-8.0

3

The

follo

win

g da

ta a

re t

he t

otal

s an

d pr

ecip

itatio

n-w

eigh

ted

mea

ns fo

r th

e 1

0-y

ea

r pe

riod

of r

ecor

d:

1982

-91

428.

67

9.06

2.

64

6.87

1.

99

20.5

5 11

.11

23.2

4 52

.73

CONVERSION FACTORS, VERTICAL DATUM, AND ABBREVIATED WATER-CHEMISTRY UNITS

Multiply By To obtain

inch (in.)foot (ft)

mile (mi)ounce, fluid (fl. oz)ounce, fluid (fl. oz)

25.40.30481.609

29.570.02957

millimetermeterkilometermilliliterliter

Water temperature in degrees Celsius (°C) can be converted to degrees Fahrenheit (°F) by use of the following equation:

In this report, "sea level" refers to the National Geodetic Vertical Datum of 1929 a geodetic datum derived from a general adjustment of the first-order level nets of the United States and Canada, formerly called Sea Level Datum of 1929..

Abbreviated water-chemistry units: In this report, specific conductance and chemical concentration are given in metric units. Specific conductance is expressed in microsiemens per centimeter at 25 degrees Celsius (îS/cm). Chemical concentration is expressed in microequivalents per liter (jieq/L). Microequivalents per liter units are used because they are the most accurate and meaningful units with which to report the chemistry of precipitation. If the reader prefers to use units of milligrams per liter (mg/L) rather than the microequivalents per liter units used in this report, values can be converted by use of the following factors:

Multiply microequivalent per liter units By To obtain milligram per liter units for:

Hydrogen (H*)Calcium (Ca2*)

Magnesium (Mg *)Sodium (Na*)

Potassium (K*)Ammonium (NHU*)

Chloride (CONitrite (NC>2~)Nitrate (NOs")

Sulfate (SO42")

0.001010.020040.012150.022990.039090.018040.035450.046000.062000.04803

H*Ca2+Mg2*Na+K+NH4*

crNO2"NO3'SO42"

Documents

Data on the Quantity and Chemical Quality of Precipitation