The primary objective of this study was to evaluate quantitatively the effects of a mixture of agricultural and non-agricultural land use practices on the chemical characteristics of the Salmon River, near Fort Langley, B.C. Present land use and geomorphic unit maps were used to determine appropriate stream sampling sites which would give an indication of the combined and separate effects of land use and geologic materials on water quality. Chemical characteristics of the Salmon River and its tributaries were monitored over a 10 month period from May 1974 until April 1975. Eighteen chemical variables were analyzed in the laboratory using Standard Methods and 5 were monitored in the field. The in situ parameters included pH, temperature, oxidation-reduction potential, specific conductance and dissolved oxygen levels. Also monitored were 7 trace metals, Cr, Cu, Fe, Mn, Ni, Pb and Zn. Atmospheric precipitation collectors were installed at the end of June 1974 and precipitation samples collected monthly from July 1974 until April 1975. Eighteen separate chemical variables were monitored at these sites using standard methods. Stream bed sediment grab samples were taken in May and again in July 1974. These_ samples were analyzed for total elemental composition as well as total nitrogen, total carbon, total sulfur, total cation exchange capacity, exchangeable cations (Ca, Mg, Na, K) and pH. The major geologic materials in the watershed were sampled in 6 sites located in undisturbed and cultivated areas on marine, glacial outwash, and alluvial materials. The monitoring of some selected chemical characteristics of the Salmon River revealed in general the mean values of pH, specific conductivity, temperature, total alkalinity, total HC03 alkalinity, total hardness (CaCO₃ equivalent), total dissolved solids, total Kjeldahl N, organic C, NO₃ -N, CI, Na, and K were consistently higher at low streamflows than at high (>750cfs) streamflows. Oxidation reduction potential and dissolved oxygen mean values were consistently higher at high flows than at low flows. The other variables measured remained relatively constant on average across all levels of streamflow. There was, however, considerable variation at specific point samples. Data derived from collection of atmospheric precipitation indicated a significant input of many chemical factors to the watershed. Bed sediment and soils chemical characteristics give a general indication of the amounts and distribution of the various chemicals potentially available for contribution to stream waters. Analysis of the results obtained in comparison with water quality standard acceptable levels revealed water quality problems with pH, temperature, phosphorus, iron, copper, and manganese. Significant statistical correlation exists between water quality variables and glaciomarine, marine and beach overlying marine or glaciomarine materials; glacial outwash materials; agricultural field crops; low density residential areas; and schools. In order to identify specific point and non-point sources more detailed information is needed on groundwater characteristics and the streamflow characteristics of tributary streams. Some general management alternatives are recommended bearing in mind that each site must be evaluated on its own merits and specific suggestions made on-site. / Land and Food Systems, Faculty of / Graduate

The Salmon River Watershed, Langley, B.C., is on the urban-rural fringe of the Greater Vancouver Regional District. A major aquifer within the Salmon River Watershed provides rural residents with drinking water and maintains stream flow during the summer. The highly mixed land use activities in the watershed, consisting of residential development, commercial agriculture and hobby farming, are resulting in non-point source nitrogen pollution of stream and groundwater. The purpose of this study was to determine how the type, intensity and changes in land use activities have affected water quality. Indicators such as nitrate-N, ammonia-N, orthophosphate, and faecal coliforms and streptococci were used to characterize water quality. Animal unit and septic system densities and nitrogen loading were used as land use indicators. Land use/water quality relationships were analyzed with a Geographic Information System (GIS). The Salmon River and its tributaries are relatively healthy. Most of the water quality indicators met the appropriate criteria for drinking water and aquatic life. Nitrate-N concentrations and microbial counts, however, have been and continue to be a concern. While nitrate-N was below the maximum drinking water quality criterion of 10 mg-N L'1 at all stations there are localized areas where nitrate-N concentrations are above background and reaching levels of concern (5 mg-N L"1). The highest nitrate-N concentrations were measured during low-flow conditions. This suggests that the nitrogen-polluted groundwater is affecting the stream during the summer. In contrast, faecal coliforms and streptocci counts were higher during high-flow conditions suggesting runoff from agricultural fields on which manure is spread in the late fall. More than 3,200 septic systems have been installed in the Salmon River Watershed between 1930 and 1994, a large number of which are located on the Hopington Aquifer. The pattern of increasing septic system densities closely matched the increase in streamwater nitrate-N from up to downstream in both the Salmon River mainstem and Coghlan Creek upstream of their confluence. Agricultural activities are concentrated on large commercial operations. However, hobby farms are becoming a more important component of the agricultural sector in the urban-rural fringe environment. There has been an overall decrease in animal numbers, mostly due to fewer cattle, poultry and pigs between 1986 and 1991. In contrast, horses and sheep, often associated with small farms, increased in number over the same time period. Animal unit densities increased from up to downstream in the Salmon River mainstem to its confluence with Coghlan Creek as does the streamwater nitrate-N concentration. In the Coghlan, however, animal unit densities did not vary, yet the nitrate-N values in this section of the stream increased the most. These results suggest that residential and agricultural uses are both sources of nitrogen in the Salmon mainstem, while septic systems are the primary source in Coghlan Creek. A nitrogen mass balance was used to quantify the sources (manure, fertilizers, the atmosphere and septic systems) and sinks (crop uptake, management losses, dentrification) of nitrogen in the watershed in order to determine the amount of surplus nitrogen being applied. The contribution of septic systems accounted for about 20 % of the surplus loading in the watershed, while large farms contributed about 68 % and small farms 12 % of the surplus loading. There is a poor linear relationship between high nitrate-N values in the stream and corresponding spatial inputs of nitrogen from manure, fertilizers and septic systems. This is due to the highly variable surficial geology, the complexity of groundwater hydrology and the spatial lag between areas of high nitrogen surplus applications and water quality sampling stations. The area near the Salmon River-Coghlan Creek confluence is the most affected section of streams in the watershed and should be used as the key site to monitor environmental quality in the watershed.

The Salmon River Watershed, Langley, B.C., is on the urban-rural fringe of the Greater Vancouver Regional District. A major aquifer within the Salmon River Watershed provides rural residents with drinking water and maintains stream flow during the summer. The highly mixed land use activities in the watershed, consisting of residential development, commercial agriculture and hobby farming, are resulting in non-point source nitrogen pollution of stream and groundwater. The purpose of this study was to determine how the type, intensity and changes in land use activities have affected water quality. Indicators such as nitrate-N, ammonia-N, orthophosphate, and faecal coliforms and streptococci were used to characterize water quality. Animal unit and septic system densities and nitrogen loading were used as land use indicators. Land use/water quality relationships were analyzed with a Geographic Information System (GIS). The Salmon River and its tributaries are relatively healthy. Most of the water quality indicators met the appropriate criteria for drinking water and aquatic life. Nitrate-N concentrations and microbial counts, however, have been and continue to be a concern. While nitrate-N was below the maximum drinking water quality criterion of 10 mg-N L'1 at all stations there are localized areas where nitrate-N concentrations are above background and reaching levels of concern (5 mg-N L"1). The highest nitrate-N concentrations were measured during low-flow conditions. This suggests that the nitrogen-polluted groundwater is affecting the stream during the summer. In contrast, faecal coliforms and streptocci counts were higher during high-flow conditions suggesting runoff from agricultural fields on which manure is spread in the late fall. More than 3,200 septic systems have been installed in the Salmon River Watershed between 1930 and 1994, a large number of which are located on the Hopington Aquifer. The pattern of increasing septic system densities closely matched the increase in streamwater nitrate-N from up to downstream in both the Salmon River mainstem and Coghlan Creek upstream of their confluence. Agricultural activities are concentrated on large commercial operations. However, hobby farms are becoming a more important component of the agricultural sector in the urban-rural fringe environment. There has been an overall decrease in animal numbers, mostly due to fewer cattle, poultry and pigs between 1986 and 1991. In contrast, horses and sheep, often associated with small farms, increased in number over the same time period. Animal unit densities increased from up to downstream in the Salmon River mainstem to its confluence with Coghlan Creek as does the streamwater nitrate-N concentration. In the Coghlan, however, animal unit densities did not vary, yet the nitrate-N values in this section of the stream increased the most. These results suggest that residential and agricultural uses are both sources of nitrogen in the Salmon mainstem, while septic systems are the primary source in Coghlan Creek. A nitrogen mass balance was used to quantify the sources (manure, fertilizers, the atmosphere and septic systems) and sinks (crop uptake, management losses, dentrification) of nitrogen in the watershed in order to determine the amount of surplus nitrogen being applied. The contribution of septic systems accounted for about 20 % of the surplus loading in the watershed, while large farms contributed about 68 % and small farms 12 % of the surplus loading. There is a poor linear relationship between high nitrate-N values in the stream and corresponding spatial inputs of nitrogen from manure, fertilizers and septic systems. This is due to the highly variable surficial geology, the complexity of groundwater hydrology and the spatial lag between areas of high nitrogen surplus applications and water quality sampling stations. The area near the Salmon River-Coghlan Creek confluence is the most affected section of streams in the watershed and should be used as the key site to monitor environmental quality in the watershed. / Science, Faculty of / Resources, Environment and Sustainability (IRES), Institute for / Graduate