Assessment of Water Quality in the Brokenhead River Watershed

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Figure 11. Total phosphorus (TP- upper panel) and the percentage of TP in dissolved form (lower panel) in the 6 subwatersheds of the Brokenhead River in 2007 (vertical bars are the standard deviation of the mean of three sampling periods). In 2007, there was a general trend of increasing total phosphorus concentration from the site located close to the headwaters of the Brokenhead River (i.e., at the Trans Canada Highway) to the sampling site downstream at Scanterbury (Figure 11 top panel). The largest step-wise increase in phosphorus concentration occurred in the northern 1/3 third of the watershed. This is also represents a significant area of transition in the watershed to more fertile clayey and loamy soils (Figure 6), better agricultural capability (Figure 8), much more agricultural land use (Figure 5) and an extensive system of agricultural drains. The phosphorus data can also be viewed in terms of the proportion of phosphorus that is in a dissolved versus particulate form (Figure 11 30 | Page
ottom panel). There is a higher percentage of the phosphorus in a particulate form (i.e., a lower percentage in a dissolved form) in subwatersheds E and F, which suggests the influence of farm drains on phosphorus export from agricultural areas. Farm drains facilitate the rapid movement of excess water from fields, which while providing clear benefits to farmers, can also increase hydraulic loading to the Brokenhead River, transport sediments (former field soils) through fastflowing, channelized flow and cause bank destabilization (Donetz, 2002). Donetz (2002) suggests that movement of water from farm drains during spring runoff and summer rain storm events may keep the Brokenhead River at a near-flood stage level, further contributing to bank erosion and increased sediment input. This can increase erosion and thus, particulate forms of phosphorus in the river. The potential influence of farm drains can also be seen in Figure 12. Concentrations of total phosphorus from late March to late September in 1995 were consistently higher upstream of the Bachman drain, compared to just downstream of the drain. Figure 12. Comparison of total phosphorus (TP) concentration upstream and downstream of the Bachman drain in the Brokenhead River in 1995 (data from Manitoba Water Stewardship). Nitrogen data collected in 2007 from the 6 subwatersheds in the Brokenhead River show a similar (although not identical) trend to the phosphorus data (Figure 13). Highest concentrations of nitrate, ammonia and total nitrogen were found in subwatersheds E and F. The trend is most evident in the nitrate (NO 3 ) data, in which concentrations are low in the subwatersheds A to D, and much higher is subwatersheds E and F. As with the phosphorus data, the nitrate concentrations may be reflecting the fact that subwatersheds E and F represent the parts of the 31 | P age
Page 1 and 2: Assessment of Water Quality in the
Page 3 and 4: Executive Summary A pilot project w
Page 5 and 6: opportunities. Based on this assess
Page 7 and 8: Table 1. Water quality sampling loc
Page 9 and 10: alkalinity, bicarbonate, carbonate
Page 11 and 12: Figure 2. Digital elevation model o
Page 13 and 14: species such as black spruce, tamar
Page 15 and 16: Figure 4. Land cover in the Brokenh
Page 17 and 18: Table 3. Land cover classes in the
Page 19 and 20: Table 4. Soil surface texture in th
Page 21 and 22: Figure 7. Soil drainage class in th
Page 23 and 24: Figure 8. Agricultural capability i
Page 25 and 26: Agricultural Activities AA-F and PF
Page 27 and 28: Figure 9. Concentration of total ph
Page 29: in the rivers. Phosphorus concentra
Page 33 and 34: Figure 13. Nitrate (NO 3 - upper pa
Page 35 and 36: Figure 15. Turbidity in the 6 subwa
Page 37 and 38: Training of Youth An important comp
Page 39 and 40: A field trip was held on May 28, 20
Page 41 and 42: Recommendations This pilot study pr
Page 43 and 44: Appendix A. Water Quality Data in t
Page 45 and 46: MB05 SAS 037 2007 Seasonal Variatio
Page 47 and 48: Appendix B. Photos of Water Quality
Page 49 and 50: MB05SAS037 (Highway 15 near Vivian)
Page 51 and 52: MB05SAS0034 (Highway 12 north of Hi

Assessment of Water Quality in the Brokenhead River Watershed

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