Scanned for KRIS

Analysis of USGS Water Quality Data

Marin Headlands GGNRA 1986-1988

by

Mary Ann Madej, Geologist

Redwood National Park

1125 16th Street Arcata, California 95521

Table of Contents

Contents Page Summary and Management Recommendations ...... 1

Analysis of USGS Water Quality Data, GGNRA ...... 3

Physical Characteristics ...... 5 Streamflow ...... 5 Water Temperature ...... 6 Specific Conductance ...... 6 PH ...... 7

Inorganic Chemical Constituents ...... 7 Alkalinity ...... 7 Arsenic ...... 7 Boron ...... 8 Cadmium ...... 8 Calcium ...... 9 Chloride ...... 9 Chromium ...... 9 Copper ...... 9 Fluoride ...... 10 Hardness ...... 10 Iron ...... 10 Lead ...... 10 Magnesium ...... 11 Mercury ...... 11 Nitrogen ...... 11 Dissolved Oxygen ...... 11 Phosphorus ...... 12 Potassium ...... 12 Selenium ...... 13 Silica ...... 13 Sodium ...... 13 Total Dissolved Solids ...... 13 Sulfate ...... 14 Suspended Sediment ...... 14 Zinc ...... 14

Organic Chemical Constituents ...... 14

Biological Constituents ...... 15 Fecal Coliform ...... 15

Comparison among sample stations ...... 15

Comparison with other water quality data ...... 18

Bibliography ...... 19

Appendix A: Summary of Water Quality Data, GGNRA ...... 20 Appendix B: Bar graphs of Water Quality Data, GGNRA ...... 24 Appendix C: USGS data sheets for Water Quality Data, GGNRA. 52

i 1

SUMMARY AND MANAGEMENT RECOMMENDATIONS

The water quality data collection program in Golden Gate National Recreation Area conducted by the U.S. Geological Survey (USGS) defined base line conditions at eight sites in the Marin Headlands. Each site was sampled twice a year, once in summer and once in winter for three years (1986-1988), for a total of six samples for the eight sites. The maximum and minimum flows for the study period were not sampled, nor was sampling timed to catch specific land use activities, such as pesticide application. Given these limitations, the following conclusions can be made. Generally water quality was good, but a few trouble spots or potential trouble areas are listed below. Recommendations for action by park management are also listed. For more detailed information on the constituents, refer to the full report.

1. The information gathered is insufficient to provide good estimates on water quantity. A regional analysis based on nearby streams gaged by the USGS can be used to supplement periodic measurements made in GGNRA. Also, a staff plate should be set up in Redwood Creek or other streams of concern and read daily, so a relationship can be constructed between stage (height of water) and discharge (volume of water) in the creeks. Discharge measurements should be made periodically throughout the year on important water courses to determine maximum and minimum flows available.

2. All springs and diversions on park lands should be thoroughly inventoried. Springs can provide cool base flow to streams during hot, dry summer conditions and are thus important for the maintenance of aquatic habitat throughout the year. Diversions may have the opposite effect by taking water out of the stream system during critical times of low flows. Water diverted for irrigation and then returned to the stream is frequently enriched in salts and may impair water quality downstream.

3. Rodeo Lagoon had a high value for pH (9.3). A high pH can be a concern for aquatic life. Photosynthesis by algae may account for the high values, and additional monitoring is necessary to see if there are diurnal fluctuations (corresponding with photosynthesis activity) or changes throughout the seasons. Rodeo Lagoon also had higher temperatures than are optimum for fish.

4. Tennessee Valley and Gerbode Valley waters had a high iron content. The iron concentration was higher than that recommended for drinking water, which gives an objectionable taste to the water and may cause staining. If the water is going to be used for a potable water supply, treatment for iron would be needed.

5. Cadmium levels in Rodeo Lagoon, Gerbode Valley and Table Rock Creeks were higher than recommended by the Environmental Protection Agency (1984) criteria. Are there any potable water supplies drawn from these creeks? Are there any waste facilities that may account for cadmium input? A waste inventory should be completed for GGNRA, taking into account the varied land use of past landowners. Periodic sampling should occur at the above sites to monitor cadmium concentrations in the future. 2

6. The concentration of lead exceeded the criterion for fish and aquatic life four times during the sampling period. The source of lead is unknown. Periodic sampling should occur at those sites to see if lead is a continued problem.

7. There is no national standard for phosphorus content in surface water. However, phosphorus concentrations at all GGNRA stations exceeded the criterion set up for Everglades National Park. The park should review its use of phosphorus-bearing materials to see if it can reduce input in the streams, and work with local landowners to do the same. Phosphorus can lead to eutrophication of surface waters, to the detriment of aquatic life.

8. For reasons unknown, Redwood Creek exhibited high copper concentrations in January, 1988. Ultra-basic bedrock in the very headwaters may be a source of copper. But because only one of six samples showed high concentrations of copper, alternative sources should be considered. Were there fungicides applied in the watershed during that time? Park management should review the policy of chemical application for control of mildew, insects, weeds, etc. and make sure no residues reach surface waters.

9. Fecal coliform are indicators of biologic contamination of surface waters. There were several problems with the coliform sampling done at GGNRA. As a result, many counts listed in the data tables are just estimates. Fecal coliform counts were high in Gerbode Valley, Green Gulch and Table Rock Creeks, and Redwood Creek at Muir Beach. Treatment of any water in GGNRA before drinking is essential. In addition, if contact recreation is a use of these waters, fecal coliform should be monitored on a regular schedule. Sources of pollution should be identified, and local landowners should be asked to cooperate in decreasing the contamination of surface waters.

10. GGNRA streams were not tested for Giardia. If this problem is a management concern for park visitation, additional sampling is necessary.

11. Suspended sediment concentrations were not high relative to other creeks in the region. However, concentrations would be expected to be much higher at the highest flows. Additional suspended sediment samples should be taken in critical areas (Redwood Creek, for example) during floods to measure the maximum concentrations of suspended sediment.

12. Surface waters were tested for 33 types of organic chemicals. Waters and bottom material were only tested once, and because most samples were below detection limits for the organic constituents no further samples were taken. These organic chemicals do not seem to pose a problem in GGNRA waters. However, the samples were not tested for the presence of pesticides and fungicides used by Banducci and the park. Waters should be sampled more thoroughly to coincide with known pesticide application or other land use activities of concern.

13. The water quality sampling program only encompassed the Marin Headlands area. Other waters under GGNRA's jurisdiction may pose other problems, such as effects from urban runoff. Problems in other areas were not addressed in this report.

3

ANALYSIS OF USGS WATER QUALITY DATA, MARIN HEADLANDS, GGNRA

The U. S. Geological Survey (USGS), under contract with the National Park Service, collected water quality samples at eight stations in Marin County in Golden Gate National Recreation Area from 1986-1988. Stations are shown on Figure 1.

The purpose of the study was to gather baseline hydrologic data to determine if the park's waters in this area are of sufficient quality to protect the ecosystem and ensure that visitors have clean water. Data collection was to provide information on the quantity, distribution and quality of surface waters within the recreation area. Each station was sampled twice a year, once during the wet season and once in the dry season. The following is an initial interpretation of the data collected by the USGS. Comparisons are also made with rivers having longer and more complete records: Russian River, Corte Madera Creek at Ross, and Arroyo Corte Madera del Presidio near Mill Valley.

Water reaches a stream through many routes, such as direct precipitation, stemflow, subsurface stormflow, and groundwater discharge. Stream water chemistry is the result of complex interactions of water from these sources. Other influences on water chemistry include the geology, climate, soil and land use in a watershed. For example, groundwater is generally higher in dissolved solids than rainfall because it has been in contact with the soil for a longer time. Groundwater in a wet climate is recharged and flushed out of the system relatively quickly, so generally has lower concentrations of dissolved ions than groundwater in drier climates. Likewise, summer concentrations of some chemicals are higher than in winter because stormflows dilute the water.

One of the sampling sites was at Rodeo Lagoon, an estuarine system that receives both saltwater and freshwater inputs. Interpretation of estuarine data will be discussed after that of freshwater systems.

Physical and chemical characteristics of the streams and Rodeo Lagoon are examined below. Each constituent is discussed separately. The emphasis is on the suitability of the waters for aquatic life. Criteria cited for the waters are summarized in Appendix 1, and are primarily based on those reported in the National Park Service WRFSL Report No. 84-4, "Water Quality Criteria: An Overview for Park Natural Resource Specialists."

In the following discussion, a distinction is made between "water quality standards" (having a legal or regulatory connotation) and "water quality criteria," a recommendation based on biological and human health considerations. Bar graphs summarizing water quality results are included as Appendix B. USGS data sheets are in Appendix C. Depending on the constituent analyzed, concentrations are listed as mg/l or as ug/l. One mg/1 = 1000 ug/l.

5

PHYSICAL CHARACTERISTICS

STREAMFLOW Winter and summer flows were measured at all the stream stations. Measurements show the range of average seasonal flows, but do not document the peak flows, nor the minimum flows occurring in these streams. Daily or continuous flow monitoring would be necessary to truly measure flow variability.

Gerbode Valley Creek showed the least variability from highest to lowest flows. Summer low flow was two orders of magnitude less than winter flows in Webb Creek and Tennessee Valley. Green Gulch, Redwood and Table Rock Creeks showed a more dramatic decrease in summer, three orders of magnitude (or one thousand times less in summer).

Runoff per unit drainage area (cfs/mi2) is one way to compare streamflows in different basins (Table 2). Winter flows are highly variable, depending on rainfall, so only those stations sampled during the same time period should be compared with one another.

Comparison of winter and summer discharges on a per unit area basis.

WINTER DISCHARGE SUMMER DISCHARGE (cfs/mi2) (cfs/mi2) (Max. of 3 samples) (Min. of 3 samples) Station# 140 Redwood at Muir Woods 27.74b 0.151 152 Redwood at Muir Beach 11.80a 0.0 154 Green Gulch 8.61a 0.009 130 Tennessee Valley 6.81a 0.021 156 Webb Creek 26.79b 0.071 158 Table Rock 31.3b 0.03 110 Gerbode Valley 2.1a 0.058 a - Sampled 1/29 - 1/31/89 b - Sampled 2/13/87

Based on the limited record, Table Rock produced the most runoff per unit area, and Redwood Creek at Muir Beach had the lowest flow (no flow) for summer months.

To fully document the quantity and variability of water supplies, a much more extensive monitoring program is needed. At a minimum, water level (stage) should be read daily on the streams of most interest. Water discharge data from nearby streams can be used to supplement GGNRA's data. An initial compilation of regional USGS data will be sent to GGNRA under separate cover.

WATER TEMPERATURE Water temperature affects algae production and other aquatic life. Temperatures also affect the solubility of chemicals. For example, the 6

ability of water to contain dissolved oxygen decreases with increasing temperature. A decrease in canopy cover can increase water temperature, with detrimental effects on aquatic life.

Seasonal water temperatures varied by several degrees. The highest temperature record was 17.5° C in Rodeo Lagoon, where the range was 12 - 17.5° C. Streams were usually, but not always, a few degrees cooler in winter than in summer. In Table Rock Creek the range was 13-14.5o C, but in March, 1988 the temperature was 1.5 greater than in June, 1988. Lower summer temperatures might be explained if Table Rock is largely spring fed. Springs are not shown in this basin on the USGS topographic map, but small springs may be identified in the field. Gerbode Valley shows a wider range (11-15o C) than Table Rock. Tennessee Valley's range was 12-15° C, Green Gulch was 12.5 - 15.5o C, and Webb Creek has the narrowest range (12-13o C). Springs, steep topography and shade along the stream channel may account for this narrow range. Redwood Creek, both below Muir Woods and at Muir Beach, had the lowest temperatures measured during this study (10.5-14o and 10-14o C respectively).

The range of water temperatures in GGNRA streams is narrower than for the nearby Corte Madera Creek near Ross, where January mean is 9o C and August mean temperature is 18o C, and for Arroyo Corte Madera del Presidio at Mill Valley where January and August means are 7° C and 21o C respectively.

Temperatures at all stations were below the lethal range for juvenile salmonids, but on occasion exceeded the upper limit of their preferred range (14.6° C). Most summer temperatures exceeded the optimum temperature of 12.2- 13.5o C for chinook and chum. Also, temperatures were not measured in August when the true maximum of the year probably occurred. Hofstra and Anderson (1989) measured maximum temperatures of 13.5o C in Redwood Creek in October, 1988.

SPECIFIC CONDUCTANCE Specific conductance is the ability of water to conduct an electrical signal, and is expressed as reciprocal ohms (mhos) at 25° C. Natural waters have specific conductances much less than 1 mho, so data are reported in micromhos (10.6 x value in mhos, or umhos). The higher ionic concentration in water, the higher the specific conductance. It is inversely related to discharge; that is, as winter flows dilute a stream, specific conductance decreases. It is also temperature dependent: for most concentrations a one degree rise is temperature increases the conductance by 2%.

All streams in GGNRA were well below the maximum critical level of 1100 to 4000 umhos suggested for fish. Specific conductance in streams in GGNRA was usually lower in winter and higher in summer, probably due to the dilution effect. Summer and winter measurements in 1988 were very similar however.

Specific conductance in Rodeo Lagoon was over one hundred times higher than in freshwater streams, due to the salinity of the estuary. Interestingly, winter measurements of specific conductance were higher than summer measurements in 1986 and 1988. 7

pH The unit "pH" is a measure of the hydrogen ion activity, or acidity, of water, and is determined by a logarithmic scale, that is, a pH decrease of one point (6.0 to 5.0) represents a ten-fold increase in acidity. The pH value in streams represents the interrelated results of many chemical equilibria. The significance can easily be misinterpreted. "pH" can be affected by the oxidation of ferrous iron, for example. As ferrous iron is oxidized, the pH can decrease more than a point.

The range of pH in streams was 6.7 to 8.5, all within acceptable limits. A general seasonal pattern emerged, with lower pH in winter, and higher in summer. The pH can be increased by photosynthesis by algae and aquatic plants, which may explain the seasonal pattern seen in GGNRA streams. All streams showed an increase in pH (i.e., a decrease in acidity) from 1986 to 1988, for reasons unknown. Rainfall totals were high in 1986, but it is not known if that could account for pH differences.

The pH measured in Redwood Creek by Hofstra and Anderson on October 6, 1988 (four months later than the USGS sampling) showed a pH 1.0 - 1.5 units lower than in June. The reason for this abrupt drop is unknown. Additional sampling with careful calibration is recommended.

Rodeo Lagoon had a high pH value of 9.3, which exceeds criteria for freshwater systems, (criteria for estuarine systems are unknown). Photosynthesis by algae may account for the high values. Further testing to determine diurnal and seasonal fluctuations is recommended.

INORGANIC CHEMICAL CONSTITUENTS

ALKALINITY Alkalinity is defined as the quantitative capacity of water to react with hydrogen ions to a pre-selected endpoint. In other words, alkalinity is a measure of the buffering capacity of the water.

Sources: Alkalinity can be produced by anions or weak acids, such as carbonic acid (when C02 is dissolved). Here is a case where the carbon and hydrologic cycles are directly linked. Silicic, phosphoric, boric and organic acids also contribute to alkalinity. Alkalinity can be expressed as the concentration of carbonate and bicarbonate, a more useful presentation than just general alkalinity.

Bicarbonate levels in most streams were <200 mg/l (except for Station 154, Green Gulch, which was occasionally higher in summer). Most streams were on the low end of alkalinity, which means they have a poor buffering capacity. For example, GGNRA streams might not be able to buffer large increases of acidity to the system through acid rain or fog. However, all measurements were above the minimum level of 20 mg/l as CaC03, recommended by the National Academy of Sciences (cited in NPS-WRFSL Report 84-4, 1984).

ARSENIC Sources: Arsenic may occur in metal veins, metallic ores and can replace phosphate in apatite. Arsenic may be added to water supplies through waste 8

disposal, and is present in certain insecticides and herbicides used in forest management and agriculture.

Drinking water criteria recommend an upper limit of 0.05 mg/l of As. All arsenic concentration values for GGNRA were much lower than that limit, and arsenic poses no threat to resources. However, Table Rock (Station 158) consistently had arsenic values 10 times higher than other stations. Webb Creek had values 2-3 times the average. These streams drain bedrock of a different lithology (with more ultra-basic rocks) which probably contributes to higher arsenic values. The history of pesticide application is these basins should also be checked.

BORON Sources: Boron is found in the mineral tourmaline, and to lesser extents, in biotites and amphiboles, minerals in igneous rocks. Boron is also found in cleaning agents, detergents, and sewage. Boron is essential to plant growth and may be applied (through manure or fertilizer) to agricultural crops.

Because of its importance to agriculture, crop tolerances to boron levels have been calculated. All stations, except Rodeo Lagoon, were considerably below the level where sensitive crops would suffer (0.5-1.0 mg/l) and by extrapolation, these waters will not harm native plants. The highest values in streams were at Stations 154 and 130 (Green Gulch and Tennessee Valley), where organic and animal wastes are readily available to leaching and runoff processes. Boron concentration was higher at these stations during the summer, probably due to low flows in the creek and the accumulation of manure. Boron concentrations at these stations were still well below critical values, however.

The concentration of boron (B) in sea water is 4.6 mg/l. Concentrations in Rodeo Lagoon ranged from 0.01 to 1.2 mg/l. No seasonal pattern was apparent.

CADMIUM Sources: Cadmium is often associated with zinc and lead ores. It is used in paint and ink pigments, plastics, electrical batteries, and fluorescent and video tubes. The recommended maximum concentration in drinking water is 10 ug/l. Cadmium levels reached or exceeded this level in February, 1987 in Table Rock Creek; in March, 1987, in Gerbode Valley; and February, 1987 in Webb Creek.

Freshwater species can be extremely sensitive to the presence of cadmium. At hardnesses of 50 and 250 mg/l as CaC03, the maximum allowable concentrations of active cadmium are 2.0 and 12.97 ug/l respectively. The limit of sensitivity in the USGS analysis was 5 ug/1. One measurement of cadmium concentration at Station 110 (Gerbode Valley) was 20 ug/l, in the toxic range for fish.

Rodeo Lagoon, with a hardness of 140-160, had cadmium values of 60 ug/l in March and June, 1987. For the protection of saltwater aquatic life, the average concentration of active cadmium should not exceed 12 ug/l during any 30 consecutive days. The normal concentration of cadmium is seawater is only 0.11 ug/l. The relatively high values in Rodeo Lagoon should be investigated. Estuarine processes tend to trap trace metals in estuarine sediments (Hem, 1985). Perhaps past land use such as for military operations resulted in some contamination. 9

CALCIUM Sources: Many igneous and metamorphic rocks contain calcium-bearing minerals, although the rate of decomposition is slow. Carbonate rocks, another source of calcium, are not present in any significant quantity in GGNRA. Cement between particles in sandstone, a common bedrock type GGNRA, can contain calcium. Also, water used for irrigation and returned to the creek frequently has higher amounts of calcium, sodium and magnesium than before irrigation. In most cases calcium is beneficial and not a management concern.

All streams in GGNRA are well below the maximum level of 75 mg/l. Most freshwater systems in humid areas have more calcium than any other location. In GGNRA, however, sodium is present in higher concentrations, due to the proximity to the ocean. Average calcium concentration of U.S. rivers is 15 mg/l, and most GGNRA streams were at that level or lower. However Green Gulch (Station 154) is twice as high in dissolved calcium as other stations. This may be related to the use of Green Gulch water for irrigation.

CHLORIDE Sources: Marine shales, precipitation near the ocean, human or animal waste. Chloride concentrations in U.S. streams are usually lower than sulfate or bicarbonate, but this is not the case in GGNRA, due to its proximity to the ocean. All streams are much lower than the maximum allowable level of 250 mg/l, except where affected by tides or ocean influxes. Sea water concentration is 19000 mg/l, and chloride concentration in Rodeo Lagoon is 5600 mg/l.

CHROMIUM Sources: Chromium is a common element in the earth's crust, and is found in air, soil and most biological systems. The chromate and dichromate forms of chromium in natural waters are usually related to industrial pollution.

The median value for the public water supplies studied by Durfor and Becker (1964, cited in Hem, 1970) was 0.43 ug/l, and for North American rivers the median was 5.8 ug/l (Hem, 1970). Values in GGNRA streams ranged from <10 ug/l to a high of 40 ug/l at Station 152 in March, 1987.

All measurements were below the critical concentration of 0.05 mg/l for drinking water. NPS (1984) states that for freshwater aquatic life the average concentration of dissolved hexavalent chromium should not exceed 0.0072 mg/l (or 7.2 ug/l) over any 30 day period. Most chromium is found in the trivalent form, where concentrations should not exceed about 850 mg/l. The relative percentages of different forms of chromium were not determined in this study, but are not considered a problem in GGNRA.

COPPER Sources: Copper-bearing minerals, herbicides, fungicides. A maximum limit of 1.0 mg/l is recommended for drinking water, and all GGNRA values are below this. However, at low alkalinities, such as are found in GGNRA, lower copper concentrations may be toxic to fish, especially juveniles (US EPA, 1976). For example at hardnesses of 50 mg/l (typical for GGNRA streams) the maximum allowable concentration of copper is 5.8 ug/l. Twenty measurements had values of 10 ug/l or more. Redwood Creek at Muir Beach (Station 152) and below Muir Woods (Station 140) both had values of 80 ug/l in January, 1988. Such 10 anomalously high values of copper should be investigated to see whether or not they are related to man's activities. Copper-bearing rocks and even old copper mines are found in northern Marin County, and may account for some of the high values measured in the streams.

FLUORIDE Sources: Fluoride is present in hornblende and micas in small amounts. Most natural waters have <1 mg/l of fluoride, and this is true for streams in GGNRA. The highest value measured was 0.4 mg/l at Station 120, which is still below the maximum level recommended by the NFS of 0.7 mg/l.

HARDNESS Sources: Hardness in nature usually results from rainwater percolating through carbonate rocks.

Hardness is a measure of bivalent metallic ions (calcium, magnesium, iron and manganese) dissolved in water. Hardness is commonly expressed as an equivalent concentration of calcium carbonate (CaC03). In fresh water, hardness is reported as carbonate and non-carbonate fractions. If total hardness exceeds alkalinity, the excess is reported as "non-carbonate" hardness. In the USGS analyses, concentration of individual constituents were computed, as well as a total hardness value. Hardness is not really a useful term with which to examine water quality. No criterion for public water supplies has been established, nor are there criteria for aquatic life. In general, hardness helps reduce metal toxicity effects.

Hardness in GGNRA streams ranged from 39 to 180 mg/l. Non-carbonate hardness ranged from 0 to 13 mg/l. Rodeo Lagoon, due to its high dissolved ion content, showed higher hardness values, which ranged from 740 to 1600. Non- carbonate hardness values in Rodeo Lagoon ranged from 640 to 1500.

IRON Sources: Many igneous rocks have iron-bearing minerals. Near-surface weathering of iron-bearing silicates produces iron accumulations. Iron is present in organic wastes and plant debris as well. Acid mine drainage can lead to extremely high iron concentrations.

The highest values measured in GGNRA were Station 130 (Tennessee Valley) and then Station 110 (Gerbode Valley). The maximum value of 0.56 mg/l was higher than recommended for drinking water, but lower than the critical level for fish (1.0 mg/l). If water is to be used for potable supplies in those areas, treatment to reduce iron is recommended. No seasonal pattern was obvious.

LEAD Sources: Lead is found in the mineral galena, certain feldspars, and old plumbing systems. Lead from gasoline and dispersed in the atmosphere as engine exhaust has increased lead concentrations in rainfall in some areas, but the importance of this effect is not known. Measurements of lead in rain at Menlo Park during the period 1971-74 showed lead concentrations ranging from 200 ug/1 to <1.0 ug/l (Hem, 1985).

The median value of North American rivers in 4.0 ug/l (0.004 mg/l) (Durum and Haffty, 1964, cited in Hem, 1970). All but four samples from GGNRA had concentrations <100 ug/l. For the protection of freshwater aquatic life, the 11 average concentration of active1 lead should not exceed 25 ug/l at hardness of 50 mg/l as CaC03. Analyses for lead were not taken to that level, but concentrations definitely exceeded this level four times. To protect saltwater aquatic life average lead concentration should not exceed 8.6 ug/l during any 30 consecutive days. Rodeo Lagoon had a value 10 times that, of 100 ug/l, in June, 1987. The average concentration of lead in seawater is only 0.03 ug/l. Stations 158, 156, and 140 (Table Rock, Webb and Redwood Creek below Muir Woods) had reading of 100 ug/l on Feburary 13, 1987. The source of this lead contamination is unknown.

1 (Operationally defined as the lead that passes through a 0.45 um membrane filter after the sample is acidified to pH 4 with metric acid.)

MAGNESIUM Sources: Serpentine and other igneous rocks. All stations (except Rodeo Lagoon) were below the maximum of 125 mg/l. Concentrations were only slightly lower than calcium, whereas in most natural waters magnesium concentrations are much lower than calcium. The mean for rivers is 4.1 mg/l, but the mean for GGNRA stations is about 10 mg/l. The abundance of serpentine bedrock in this area probably accounts for relatively high magnesium concentrations.

Magnesium salts in water can affect the toxicity of copper (also high locally in GGNRA) to fish. The effects of magnesium salts on different species vary considerably. For example, a concentration of 300 mg/l is toxic to the stickleback (NPS, 1984). Stickleback are found in freshwater and estuarine systems in GGNRA. Rodeo Lagoon exceeded this level (320 mg/l) in summer, 1987.

MERCURY Sources: Disposal of mining wastes, or certain industrial wastes.

Drinking water should not exceed 1 or 2 ug/l (depending on the standard used). The maximum concentration measured was 0.2 ug/l in Gerbode Valley (Station 110) in March, 1988, lower than the limit for drinking water. This is, however, the limit acceptable for the protection of freshwater aquatic life. Because streams met, but did not exceed, this critical value, mercury is not considered a problem at this time in GGNRA.

NITROGEN Sources: Atomspheric inputs, biological fixation, effluent from sewage treatment plants, or runoff from fertilized fields.

Nitrogen levels reported are the result of dissolved nitrates and nitrites. The USGS made no separation of the two constituents. All streams were well below the 10 mg/l maximum for nitrate, and probably lower than the 1.0 mg/l reported for nitrite. Stricter standards exist for some waters. In Everglades National Park, for example, the maximum nitrate standard is 0.7 mg/l, and that for nitrite is 0.04 mg/l. GGNRA waters occasionally exceeded these stricter standards.

DISSOLVED OXYGEN Dissolved oxygen is an important constituent in water quality, and is a factor in the maintenance of aquatic life. Dissolved oxygen content may be reported in terms of actual concentration or as a percentage of saturation. 12

In a stream system, dissolved oxygen concentration will depend on organic waste loading (biochemical oxygen demand), the rate of atmospheric reaeration, photosynthesis, and respiration (NFS, 1984). Insufficient dissolved oxygen can lead to unsuitable conditions for aquatic life. For example, growth rate, food consumption rate and efficiency of food utilization of juvenile coho salmon decrease when dissolved oxygen is 4 or 5 mg/l.

All values measured in GGNRA were above the minimum acceptable level for fish. The low value in the period of record was 6.3 mg/l in Green Gulch, in June, 1988. Dissolved oxygen values may be lower than those reported. No measurements were taken at the lowest flow in the season (August to September), before several of the streams went dry. Dissolved oxygen values measured by NPS staff on October 6, 1988 (Hofstra, personal communication) were as low as 1 mg/l in downstream Redwood Creek.

Dissolved oxygen was usually higher in winter, because flows are faster (increasing aeration) and biological demand is less. The two exceptions were Webb and Table Rock Creeks in 1986.

Percent saturation of dissolved oxygen varied from only 61% in Green Gulch in June, 1987 to near 100% for all streams in the winter.

PHOSPHORUS Sources: Sewage, fertilizers and animal wastes are the most common sources of orthophosphorus in streams. Apatite is a phosphorus-bearing mineral found in some igneous rocks and marine sediments.

No drinking water criterion for phosphorus has been established. Standards for phosphorus are usually established according to the degree of protection a state wishes to afford a particular water. For example, the maximum allowable mean annual concentration for soluble phosphorus in delivery water to Everglades National Park is 0.020 mg/l. California State waters may reach 0.100 mg/l. All streams met or exceeded the more stringent 0.02 mg/l limit. Station 158 exceeded the California maximum once and had the highest concentration of all streams measured (0.29 mg/l, or more than ten times the maximum level recommended for the Everglades). Station 130 met or exceeded the Everglades standard four times, Station 156 three times, Station 110 and 152 one time, and Station 140 had a concentration of 0.08 mg/l in February, 1987.

Seawater has an average phosphorus concentration of 0.07 mg/l. Rodeo Lagoon had a maximum concentration of 0.08 mg/l in March, 1987. Although not extremely high, phosphorus should be considered a management concern. Phosphorus-rich waters can create problems with algal blooms, aquatic weeds, and reduction in number of desirable fish. Phosphorus concentrations in GGNRA streams can be reduced by minimizing inputs from sewage, septic tanks and fertilizers.

POTASSIUM Sources: feldspars, micas, clay minerals. Potassium is also present in the ash of plants. Grass fires, for example, can increase potassium levels. It is also a common component of fertilizers. 13

Usually streams have much lower potassium concentrations than sodium, and this is true in GGNRA. Most rivers have similar concentrations at high and low flows. There was some variance in potassium levels in GGNRA streams, but no seasonal pattern was discernable. Concentrations for all stations were well below critical levels for fish (400 mg/l). Stations 110 (Gerbode Valley) and 130 (Tennessee Valley) had the highest concentrations, 1.8 and 2.2 mg/l respectively. Maximum concentration of potassium in Rodeo Lagoon was 110 mg/l. The average concentration for seawater is 380 mg/l.

SELENIUM Source: Selenium is frequently associated with industrial waste or agricultural usage. All streams were well below the critical level for selenium.

SILICA Sources: Silicon is second only to oxygen in abundance in the earth's crust. Many minerals have silicon. The bond between silicon and oxygen is very strong and the term "silica," meaning the oxide Si02, is widely used in referring to silicon in natural waters. Quartz is a common mineral made of silica, but is relatively insoluble. Chert is a little more soluble and is common throughout the Marin Headlands. Chert content in bedrock decreases north of Tennessee Valley. Most silica in natural waters results from the breakdown of silica minerals in the process of weathering. The solubility increases as temperature increases.

Most natural waters contain 1-30 mg/l, with an average of 14 mg/l. GGNRA streams fall within this range. Table Rock consistently showed higher concentrations than others, although its basin does not have a large amount of chert. Because the silica content does not pose a problem, further investigation is not warranted.

SODIUM Sources: Feldspars in igneous rocks, and salt spray from the ocean.

The criterion for a maximum sodium concentration in drinking water of 20 mg/l was met or exceeded 14 times in GGNRA streams. The proximity to the ocean probably accounts for the high levels. Station 154 (Green Gulch) was twice as high as other streams, and 5 of its 6 samples were > 20 mg/l. The use of water for irrigation may increase its sodium content. All freshwater stations were well below toxic levels for aquatic life, so sodium is not considered a problem.

Winter concentrations were slightly lower than summer ones for most stations, due to dilution by stormflows.

Sodium levels in Rodeo Lagoon varied from 1300 to 3300 mg/l. The average for seawater is considerably higher, 10,500 mg/l. This fact emphasizes the importance of freshwater input to estuaries.

TOTAL DISSOLVED SOLIDS Dissolved solids in natural waters primarily include carbonates, bicarbonates, chlorides, sulfates, and phosphates. All dissolved salts change the physical and chemical nature of water. The drinking water criterion for domestic water supplies should not exceed 500 mg/l dissolved solids. Most 14

U.S. waters that support varied fish populations have dissolved solid concentrations below 400 mg/l. Most streams in GGNRA range from 100 to 250 mg/l, and the maximum concentration recorded was 290 mg/l at Station 154 (Green Gulch) in June, 1987. Concentration of dissolved solids in Rodeo Lagoon varied from 4300 to 10,000 mg/l, due to the salinity of the estuary.

SULFATE Sources: Sulfates are present in some igneous and sedimentary rocks. A common sulfur-bearing mineral is pyrite. Air pollution from fuel combustion can increase sulfates in precipitation. In humid areas sulfates appear in water leached from shales and other sedimentary rocks.

All streams in GGNRA were much lower than the maximum concentration for drinking water of 250 mg/l. Ninety five percent of U.S. waters that support good game fish have less than 90 mg/l of sulfate. The highest concentration in GGNRA streams was only 26 mg/l.

Rodeo Lagoon had a maximum concentration of 750 mg/l, compared to the concentration of S04 in seawater of 2700 mg/l.

SUSPENDED SEDIMENT Most suspended solids in natural waters are composed of silt and clays eroded from the hillslopes, organic detritus and plankton. High suspended sediment concentrations can cause abrasive injuries to fish, suffocate eggs and destroy the quality of spawning beds. Suspended sediment concentrations in GGNRA streams were low, however (4 to 162 mg/l) and under these conditions pose no threat to the resources. Sediment concentration should be measured at the highest flows, though, when concentrations are likely to be highest to determine the full range of suspended sediment.

ZINC Sources: The zinc ore sphalerite, and in some igneous-rock minerals zinc may replace iron or magnesium. It may be dissolved from galvanized pipe, and may be present in industrial waste.

The recommended upper limit for zinc in drinking water is 5.0 mg/l. All GGNRA streams had values far lower than this. However, to protect freshwater aquatic life, the American Fisheries Society (1979) recommended a maximum concentration of 0.05 mg/l for waters with a hardness of 0-150 mg/l as CaC03. Four streams (Stations 110, 130, 154, and 156) each had one winter measurement that exceeded this level, but the cause is unknown.

ORGANIC CHEMICAL CONSTITUENTS The selection of organic target compounds is difficult. More than 60,000 synthetic organic compounds are used in manufacturing processes today; moreover, the number of byproducts and degradation products from these compounds is unknown. Only a small fraction of the total number can be measured by using existing analytical techniques (Hirsch et al, 1988). Analysis for some organic chemicals may show low concentrations or the absence of such chemicals, while others, possibly more important, go unnoticed. 15

The USGS tested the water and bottom materials from GGNRA's eight stations for 33 organic chemicals, such chlordane and malathion. These chemicals are listed in the data tables. The waters were only analyzed one time for these chemicals, either in the winter or summer of 1986. Most samples had concentrations less than the detection level, so this phase of the sampling program was discontinued.

None of the chemicals tested by the USGS are officially used in GGNRA at present. Nine compounds were listed by Banducci to be used as fungicides and herbicides. GGNRA lists at least eight pesticides used. Other chemicals may be used by state and county road maintenance crews or other landowners. A thorough inventory of chemicals used on or adjacent to GGNRA lands should be completed. If the park is concerned with the possible contamination of waters by agricultural practices, additional sampling should take place at the time of chemical application, and during the first runoff event, above and below possible source points in the creeks. Waters should be analyzed for the specific chemical of concern.

BIOLOGICAL CONSTITUENTS FECAL COLIFORM Coliform bacteria are considered to be the primary indicators of fecal contamination, and as such are some of the most frequently applied indicators of water quality. Drinking water must be free of coliform organisms at the time of consumption, and raw water should have less than 2000 total coliforms/100 ml prior to treatment. For contact recreation waters, based on a minimum of five samples taken over a 30-day period fecal coliform levels should not exceed a log mean of 200 organisms per 100 ml, nor should more than 10 percent of the total samples taken during any 30-day period exceed 400 organisms per 100 ml (ERA, cited in NPS, 1984).

In GGNRA streams, the USGS did not sample frequently enough to determine if the water met the ERA criteria cited above. In addition, 24 of the samples were questionable due to problems with the cultures. Questionable values are reported with a ‘K’ on the data sheets. Based on available data, coliform counts were unacceptably high in some areas, not only for drinking water, but also for contact recreation. Gerbode Valley, during the winters of 1986 and 1987 had concentrations of 1200 and 4300 colonies/100 ml. Two samples in Tennessee Valley, one in Green Gulch, and one Table Rock Creek were over 400 colonies/100 ml. Redwood Creek at Muir Beach (Station 152) was the worst offender with a high of 8000 colonies/100 ml in March, 1987. In Rodeo Lagoon, maximum counts were 2100 colonies/100 ml of fecal coliform in March, 1987, and 4600 colonies/100 ml of Streptococci coliform in March, 1987. If park is concerned about use of these waters by visitors, a more frequent and rigorous sampling program should be initiated.

COMPARISON AMONG SAMPLE STATIONS Figures 2 and 3 show the cumulative percentage of major inorganic chemical constituents measured at the eight stations in GGNRA. Each percentage represents the average of six samples taken by the USGS, 1986-1988, three in winter and three in summer. These graphs provide an easy way of comparing different stations. They show that all stations, except for Rodeo Lagoon, have very similar chemical make-ups. Freshwater stations vary the most in chloride content. Tennessee Valley (Station 130) had the highest average percentage of chloride, while Redwood Creek at Muir Woods had the lowest. 16

Figure 2: Cumulative percentage of dissolved ions at Stations 120, 153, 110, and 130. 17

Figure 3: Cumulative percentage of dissolved ions at Stations 154, 152, 140 and 156. 18

Chloride concentration is largely dependent on the proximity to the ocean. Otherwise silica and calcium, benign chemicals, account for the largest differences among streams. The similar bedrock, soils, climate, vegetation and land use in these basins result in similar chemical characteristics of these streams. Klein (USGS, 1989) presents a trilinear Piper diagram based on 1988 data which illustrates the same point.

Because of the saltwater influence on Rodeo Lagoon, sodium and chloride dominate its chemical picture. The line representing Rodeo Lagoon (Station 120) on Figure 2 is noticeably different from those of the freshwater stations for this reason.

COMPARISON WITH OTHER WATER QUALITY DATA Wahrhaftig and Lehre (1974) cited several sources of periodic water quality sampling. Most of this information was gathered from well sampling. Wells intercept more groundwater, and may have different compositions than surface water. Hardness, alkalinity, and total dissolved solids were higher in the wells for this reason. Concentrations of dissolved ions such as calcium, magnesium, sulfate, chloride and of silica were similar to surface water concentrations, and iron concentrations were less. Two wells did show high concentrations of chloride (400-500 mg/1) and may be intercepting saltwater. The pH values range from 6.9 to 8.0, a narrower range than surface water measurements. If GGNRA needs to know the quality of its subsurface water, additional monitoring is needed. Extrapolation from surface water data should not be used.

The Russian River near Guerneville is the closest USGS station with water quality data. The Russian River has higher summer temperatures (22° C) than the smaller streams in GGNRA. GGNRA streams show a wider range in pH, specific conductivity, dissolved solids, calcium, sulfate, and nitrogen concentrations. GGNRA values of chloride and sodium are higher, due to its proximity to the ocean. Concentrations of arsenic, cadmium, chromium, copper, iron, lead, mercury, nitrogen and fluoride are higher in GGNRA streams. Because water quality is so dependent on local geology, soils and land use, long-term water quality sampling at the Russian River should not be used as a surrogate for GGNRA streams. 19

BIBLIOGRAPHY

American Fisheries Society, 1979, A Review of the ERA Red Bood: Quality Criteria for water. American Fisheries Society, Water Quality Section, Bethesda, Maryland, 313 p.

Hem, J.D., 1985, Study and interpretation of the chemical characteristics of natural water (3rd ed.): U.S. Geological Survey Water-Supply Paper 2254, 223 p.

Hirsch, R. M., W. M. Alley, and W. G. Wilbur, 1988, Concepts for a national Water-Quality Assessment Program, USGS Circular 1021, 42 p.

Hirsch, R. M., Slack, J. R., and Smith, R. A., 1982, Techniques of trend analysis for monthly water-quality data: Water Resources Research, v. 18, p. 107-121.

Hofstra, T.D., and D.G. Anderson, 1989. Preliminary analysis of fishery resources of Redwood Creek, Marin County, California. NPS in-house report.

National Academy of Sciences, 1973. Water quality criteria 1972. EPA Ecol. Res. Series EPA-R3-73-033. U.S. Environmental Protection Agency, Washington, D.C. 594 p.

National Park Service, 1984, Water Quality Criteria: An Overview for Park Natural Resource Specialists, Water Resources Field Support Laboratory Report No. 84-4, 46 p.

Nemerow, N. L., 1974, Scientific Stream Pollution Analysis, McGraw-Hill, New York, 358 p.

Reiser, D.W. and T.C. Bjornn, 1979, Influence of Forest and Rangeland Management on Anadromous Fish Habitat in Western North America: Habitat Requirements of Anadromous Salmonids, USDA Forest Service General Technical Report PNW-96, 54 p.

Rosendahl, P. C., and P. W. Rose, 1979. Water quality standards: Everglades National Park. Environmental Management 3(6)-.483-491.

U.S. Environmental Protection Agency, 1976, Quality criteria for water. Government Printing Office, Washington, D.C., 256 p.

Wahrhaftig, C., and A. Lehre, 1974, Geology and hydrology of Golden Gate National Recreation Area. In-house report, 246 p.

U.S. Environmental Protection Agency, 1984, Water quality criteria, Federal Register 49(26):4551-4554, February 7, 1984. Washington, D.C. 52 p.

World Health Organization, 1971. International standards for drinkingwater. 3rd ed. Geneva. 72 p.

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Appendix A

SUMMARY OF WATER QUALITY DATA, GGNRA

Constituents Criteria (NPS)1 GGNRA Range Criteria From

Alkalinity Minimum of 20 mg/l Minimum of 29 mg/l >20 mg/l for fresh- for fish & wildlife at Sta. 110 in water organisms, Maximum of 400 mg/l winter, 1987; 35-200 mg/l Maximum of 176 mg/l for wildlife2 at Sta. 154, summer, 1987.

Arsenic Maximum of 0.05 mg/l Maximum of 0.014 Maximum of 0.05 mg/l at Sta. 158, mg/l2 summer, 1986.

Boron Maximum of 10 mg/ Maximum of 1.3 Maximum of 1.0 mg/l2 in freshwater mg/l at Sta. 120 summer, 1987. Maximum in fresh- water of 0.11 mg/l, summer, 1986, at Sta. 154.

Cadmium Maximum of 0.002 Maximum of 0.06 Maximum of 0.01 mg/1 when hardness mg/l at Sta. 120, mg/l for drinking 4 is 50 mg/l as CaC03 winter and summer, water in freshwater; 1987; maximum in 0.012 mg/l in freshwater of 0.02 saltwater mg/l at Sta. 110, winter, 1987.

Calcium Maximum of 75 mg/l Maximum of 110 mg/l at Sta. 120, summer, 1987. Maximum in freshwater 36 mg/l at Sta. 154, summer, 1987.

Chloride Maximum. of 250 mg/l Maximum of 5600 mg/l Maximum of 100 in freshwater at Sta. 120, summer, mg/l3 1987. Maximum in freshwater of 50 mg/l at Sta. 154, summer, 1987.

Chromium Maximum of 0.050 Maximum of 0.04 mg/l Maximum of 1.0 mg/l Sta. 152, winter, mg/l2 1987.

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Constituents Criteria (NPS)1 GGNRA Range Criteria From

Coliform, Maximum of 2000 Maximum of fecal For contact recrea- Fecal and coliforms/100 ml coliform 8000 col/ tion, should not Total 100 ml at Sta. 152, exceed a log mean winter, 1987. of 200 col/100 ml2 Maximum Streptococci Coliform of 23,000 col/100 ml at Sta. 130, winter, 1987.

Copper Maximum of 1.0 Maximum of 0.08 mg/1 Maximum of 1.0 mg/l for drinking Sta's 152 & 140, mg/l2 water, 0.005 - winter, 1988. 0.015 mg/l for fisheries, 0.002 mg/l for saltwater

Fluoride Maximum of 0.7 - Maximum of 0.4 mg/l 1.2 mg/l Sta. 120, winter, 1988.

Hardness No criteria for Minimum of 35 mg/l; drinking water, or maximum of 1600 mg/l wildlife at Sta. 120, summer 1987. Maximum in freshwater 180 mg/l at Sta. 154, summer, 1987.

Hardness No criteria for Minimum of 1.0 mg/l (Non drinking water at Sta. 140, winter, Carbonate) or wildlife 1986. Maximum in freshwater of 13 mg/l at several stations; maximum of 1500 mg/l at Sta. 120, summer, 1987

Iron Maximum of 0.3 Maximum of 0.56 mg/l Maximum of 0.3 mg/l for domes- at Sta. 130, summer, mg/l2 tic water, 1.0 1987. mg/l for fish

Lead Maximum of 0.05 Maximum of 0.10 mg/l 0.05 mg/l4 mg/l for drinking at Sta's 120, 158, water. For fish 140 and 156. maximum of 0.25 mg/l at hardness of 50 mg/l as CaC03

22

Constituents Criteria (NPS)1 GGNRA Range Criteria From

Magnesium Maximum of 125 mg/l, Maximum in freshwater unless sulfates of 21 mg/l at Sta. 154, exceed 250 mg/l summer, 1987. Maximum in which maximum of 320 mg/l at Sta. 120 magnesium summer, 1987. is 30 mg/l.

Mercury Drinking water, Maximum of 0.0002 mg/l maximum of 0.001 at Sta. 110, winter, mg/l. For fish, 1988. maximum is 0.002 mg/l

Nitrogen Maximum of 10 mg/l Maximum of 1.0 mg/l In Everglades mg/l for nitrate, at Sta. 154, winter, N.P., maximum maximum of 1.0 mg/l 1986. nitrate standard for nitrite is 0.7 mg/l, maximum nitrite is 0.04 mg/l

Oxygen No criteria for Minimum of 6.3 mg/l Must be > 4 mg/l2 (Dissolved) drinking water. at Sta. 154, summer, Must be 3.0 mg/l 1988. Maximum of or more for fish. 11.8 mg/l at Sta. 158, summer, 1988.

PH For drinking water, Minimum of 6.70 at For public waters between 6.5 and 8.5, Sta. 110, winter, 6.0 - 8.5 for for freshwater fish 1986. Maximum of fish 6.0 - 9.02 between 6.5 - 9.0 9.3 at Sta. 120, summer, 1988.

Phosphorus No standard for Maximum of 0.29 mg/l In Everglades N.P. drinking water at Sta. 158, winter maximum is .020 1987. mg/l

Potassium Maximum of 1000 to Maximum in freshwater 2000 mg/l for was 2.2 mg/l at Sta. public use, 400 130, winter, 1987. mg/l for fish Maximum of 110 mg/l at Sta. 120, summer,

1987.

Selenium Maximum of 0.01 mg/l Less than 0.001 mg/l 0.01 mg/l4 for domestic water for all Stations.

Silica Maximum of 20.0 mg/l at Sta. 158, summer, 1988.

23

Constituents Criteria (NPS)1 GGNRA Range Criteria From

Sodium Maximum of 20 mg/l Maximum in fresh for drinking water, water of 40 mg/l 500 - 1000 mg/l for at Sta. 154, summer, fish 1987. Maximum of 3300 mg/l at Sta. 120, summer, 1987.

Specific No criteria for Maximum in fresh- Conductance public use. water of 578 umhos at Maximum 1100 - 4000 Sta. 154, summer, umhos at 25°C for 1987. Maximum of fish 16,300 umhos at Sta. 120, summer, 1987.

Sulfate Maximum of 250 - Maximum in fresh Maximum of 90 mg/l3 500 mg/l water of 26 mg/l at Sta. 154, summer, 1986. Maximum of 730 at Sta. 120, summer, 1987.

Total For fish, <400 mg/l Maximum in fresh- 500 mg/l4 Dissolved is recommended water is 290 mg/l Solids at Sta. 154, summer, 1987. Maximum of 10,000 mg/l at Sta. 120, summer, 1987.

Zinc Maximum <5.0 mg/l Maximum of 0.18 mg/l Maximum of 0.05 at Sta. 110, mg/l1 winter, 1986.

1 NPS – WRFSL Report No. 84-4 2 N. L. Nemerov, 1974, Scientific Stream Pollution Analysis 3 McKee and Wolf, 1963, Water Quality Criteria. 4 Drinking Water Standards, EPA, 1975, 1977.

Assume mg/l = ppm, 1 ppm = 1 mg/kg, and 1 ug/l = .001 mg/l