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

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

THE SEDIMENT SYSTEM

Erosion Transportation Deposition - on land/instream

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.

EROSION

Flowing water Wind Gravity Biological Activity Water Waves Flowing Ice

TRANSPORTATION

Movement of material detached by erosion

Factors effecting runoff and erosion:

Gravity Climate GeologyLand Use Soil

Topography Vegetation

DEPOSITION

Coming to rest of transported material

Can be temporary or permanent

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

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

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

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).

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)

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)

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

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

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

What decisions can be made from sediment data?

(cont.) After dam removal:1. Where did sediment end up2. How much was deposited in channel3. How much flushed out4. How long will it take to restore river to

pre-dam conditions5. Did fish return, what fish returned6. What was learned in one removal

can be used in the next

What decisions can be made from sediment data?

(cont.) In restoring stream to natural

conditions- local economy effected1. How many jobs needed and created2. Did salmon and other fish recover3. Did ancestral tribal fisheries return4. Increase in target businesses- angling,

rafting, recreation, tourism, commercial fishery (less dollars for disaster relief)

5. Riverfront property values increase6. Public health improves

Types and parts of a sediment record

Daily, periodic, event based Water discharge Sediment concentration Particle Size analysis Water Temperature

BASIC TRANSPORT, LOAD, COMPUTATION

Transport curve method:

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

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)

What are your reasons to collect sediment?