Figure 1. Typical hydrologic cycle for eastern North Carolina  3

Figure 2. Schematic of the two zone Riparian Forest Buffer System  9

Figure 3. Stream order designations 11

Figure 4.  Conceptual model of below-ground processes affecting ground water nutrients in riparian forest  14

Figure 5.  Nitrate concentrations in ground water beneath riparian forests 14

Figure 6.  Surface drainage system 19

Figure 7a.  Controlled drainage showing flashboard riser 20

Figure 7b. Water profile in drainage ditch upstream of flashboard riser 20

Figure 8a. Average annual outflows measured from 14 sites in eastern North Carolina. The values shown represent approximately 125 site-years of data  21

Figure 8b. Average annual nitrogen transport (TKN and NO3-N) in drainage outflow as measured at the field edge for 14 soils and sites 21

Figure 8c. Average annual total phosphorus transport in drainage outflow as measured at the field edge for 12 soils and sites. Values shown are for mineral soils only. Two sites with organic soils were not included 22

Figure 9.  Water table depth in relationship to stream location 28

Figure 10. Controlled drainage 30

Figure 11. Landscape Middle Coastal Plain 31

Figure 12. Relationship between landscape position, water table depth, and soil series in the Middle Coastal Plan  32

Figure 13. Relationship between soil and saprolite 32

Figure 14. Shrub buffer 34

Figure 15. Depth of ground water for effective nitrate control 35

Figure 16. Mineralogy from Chapel Hill to Raleigh 36

Figure 17. Recommended riparian buffer 37

Figure 18. Detailed cross-section of level spreader trench for dispersing runoff along the contour 38

Figure 19. Design of level spreader used for dispersing agricultural runoff through a forested riparian buffer 39

Figure 20. Pasture stream with fenced riparian buffer 39
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