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REASON FOR COLLECTING SEDIMENT DATA

REASON FOR COLLECTING SEDIMENT DATA. Designed for Native Americans in Oregon & Washington -------------------------------------------- Confederated Tribes of Siletz- Siletz, and Coquille Tribes Umatilla Tribe, Pendleton, OR -------------------------------------------- Cowlitz Tribe.

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REASON FOR COLLECTING SEDIMENT DATA

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  1. REASON FOR COLLECTING SEDIMENT DATA Designed for Native Americans in Oregon & Washington -------------------------------------------- Confederated Tribes of Siletz- Siletz, and Coquille Tribes Umatilla Tribe, Pendleton, OR -------------------------------------------- Cowlitz Tribe

  2. TO BE COVERED • THE SEDIMENT SYSTEM • DETRIMENTAL EFFECTS OF SEDIMENT IN RIVERS • SEDIMENT DATA NEEDS • WHY COLLECT SEDIMENT DATA AND HOW IS IT USED • WHAT DECISIONS CAN BE MADE • SEDIMENT RECORDS

  3. THE SEDIMENT SYSTEM • Erosion • Transportation • Deposition - on land/instream

  4. Fluvial Sediment Transport The fluvial system commonly is conceptualized into three process-dominated zones: (1) the upper source zone, (2) the middle transfer zone, and (3) the lower accumulation zone (Schumm, 1977) (Figure 1). This macroscopic conceptual model generally is applicable for large, coastal-draining river systems, and all three of the general processes; erosion, transport, and deposition; occur to varying degrees in each zone. Sediment transport processes associated with flowing water begin when earth material is entrained and terminate when the material either is deposited or dissolved. Fluvial deposits, including instream bars and benches, floodplains, and deltas, are either temporary and remobilized or permanent and converted to sedimentary rock over geologic timescales.

  5. EROSION • Flowing water • Wind • Gravity • Biological Activity • Water Waves • Flowing Ice

  6. TRANSPORTATION • Movement of material detached by erosion • Factors effecting runoff and erosion: Gravity Climate Geology Land Use Soil Topography Vegetation

  7. DEPOSITION • Coming to rest of transported material • Can be temporary or permanent

  8. DETRIMENTAL EFFECTS OF SEDIMENT IN RIVERS • Reducing storage capacity of reservoirs- Cowlitz Basin • Causing changes in channel configuration- Siletz & Umatilla Basins • Slowing or halting, either temporarily or permanently, plant growth when deposited on productive Tribal land

  9. DETRIMENTAL EFFECTS OF SEDIMENT IN RIVERS (cont.) • Altering or destroying aquatic and fish-spawning habitat- Siletz Basin-lamprey • Creating turbidity that reduces photosynthetic activity which a healthy stream requires- Klamath Basin • Degrading water for consumptive use • Increasing the cost of water treatment by damaging distribution systems and need to remove sediment from filters City of Salem

  10. DETRIMENTAL EFFECTS OF SEDIMENT IN RIVERS (cont.) • Acting as a carrier of other pollutants, such as nutrients, insecticides, and heavy metals • Acting as a carrier of bacteria and virus • Causing stream to not meet its intended use, i.e. would need TMDL

  11. SEDIMENT DATA NEEDS • The evaluation of sediment yields with respect to different natural environmental conditions • The evaluation of sediment yields with respect to different kinds of land use • The evaluation of the differences between these two (how much is natural, how much anthropogenic).

  12. SEDIMENT DATA NEEDS (cont.) • The evaluation of erosion and deposition in channel systems • The amount and size characteristics of sediment delivered to a body of water (fines vs coarse material) • The relationship between sediment, water quality, and biota (holistic approach)

  13. SEDIMENT DATA NEEDS (cont.) • The characteristics of sediment deposited as related to particle size and flow conditions (track to source areas, Oregon Coastal rivers) • The time distribution of sediment concentration and transport rate in a stream (input from tributaries) • Wood R- restore upper meander-belts & reconnect to lower channel (drained)

  14. Why collect sediment data and how is it used ? • Channel and lake restoration, retrofit dams for fish passage & temp control • Need to track sediment transport over time- getting better/worse • Background data to establish trends • Channel navigation- dredge rivers for shipping and commerce • Driven by a legal mandate- TMDL, Endangered Species, WQ constituent

  15. Why collect sediment data and how is it used ? (cont.) • Relate to fish survival and recovery (is sediment covering fish eggs, or making it difficult to see prey • Understand the flux of sediment from land to water (hazards, landslide studies, fire and burned areas, road building, agriculture, cropland) • Other pollutants will attach to sediment (DDT) ; measure sed chemistry

  16. What decisions can be made from sediment data? • Define areas for remediation and restoration- where sediment ends up • Define source areas of sediment to reduce or eliminate transport – where sediment comes from • Mobilize dredging operations to specific areas (Oregon Coast) • Design and engineer bridges, roads, dams, and infrastructure to withstand sediment forces and volumes

  17. What decisions can be made from sediment data?(cont.) • After dam removal: • Where did sediment end up • How much was deposited in channel • How much flushed out • How long will it take to restore river to pre-dam conditions • Did fish return, what fish returned • What was learned in one removal can be used in the next

  18. What decisions can be made from sediment data?(cont.) • In restoring stream to natural conditions- local economy effected • How many jobs needed and created • Did salmon and other fish recover • Did ancestral tribal fisheries return • Increase in target businesses- angling, rafting, recreation, tourism, commercial fishery (less dollars for disaster relief) • Riverfront property values increase • Public health improves

  19. Types and parts of a sediment record • Daily, periodic, event based • Water discharge • Sediment concentration • Particle Size analysis • Water Temperature

  20. BASIC TRANSPORT, LOAD, COMPUTATION • Transport curvemethod: Q (x-axis) vs Conc (y-axis) Qs = sediment discharge) • Concentration curve developed for daily discharge (traditional approach) • Qs = K*Conc (mg/L) *Q = tons/day • Sediment surrogate- instream sensor reading (such as turbidity or voltage, on x-axis vs Conc in mg/L on y-axis

  21. Summary • We are measuring the transport phase of the sediment cycle • Collect data to determine the detrimental effects of sediment in rivers • Use data to compute sediment transport (tons per day)

  22. What are your reasons to collect sediment?

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