Hydrology: Discharge, Hydrographs, Floods, and Sediment Transport - PowerPoint PPT Presentation

Loading...

PPT – Hydrology: Discharge, Hydrographs, Floods, and Sediment Transport PowerPoint presentation | free to download - id: 107fb3-MmU0Z



Loading


The Adobe Flash plugin is needed to view this content

Get the plugin now

View by Category
About This Presentation
Title:

Hydrology: Discharge, Hydrographs, Floods, and Sediment Transport

Description:

Hydrology: Discharge, Hydrographs, Floods, and Sediment Transport. Unit 1: Module ... Hydrology is one of the primary factors influencing the physical and biological ... – PowerPoint PPT presentation

Number of Views:380
Avg rating:3.0/5.0
Slides: 26
Provided by: valuedg594
Category:

less

Write a Comment
User Comments (0)
Transcript and Presenter's Notes

Title: Hydrology: Discharge, Hydrographs, Floods, and Sediment Transport


1
Hydrology Discharge, Hydrographs, Floods, and
Sediment Transport
  • Unit 1 Module 4, Lecture 2

2
Objectives
  • Students will be able to
  • interpret hydrographs.
  • explain the effects of urbanization on storm
    hydrographs.
  • describe factors that influence overland flow of
    water.
  • describe patterns of deposition based on particle
    size in a stream bed.
  • explain how sediment load is related to discharge.

3
Hydrology
  • Exhibits wide variation across watersheds
  • Related to
  • Precipitation
  • Geology (including topography)
  • Landuse land cover
  • Hydrology is one of the primary factors
    influencing the physical and biological
    characteristics of streams

4
Discharge
  • Q - Volume of water passing a point per unit
    time.
  • QVA or WDV

5
Discharge and hydrographs
6
Annual hydrographs
7
Storm hydrograph
8
Effects of urbanization on a storm hydrograph
9
Flow paths
10
Overland flow
  • Occurs when soils are
  • saturated (after snow melt or heavy rain)
  • have low permeability (e.g., clay)
  • Strongly influenced by landform and land use
  • Coarse textured glacial deposits are highly
    permeable bedrock ancient lake bottoms are
    impermeable or have low permeability
  • Impervious surfaces (parking lots, structures)
    create impervious surfaces
  • Forest harvest practices and agricultural
    practices affect stream flow

11
Overland flow and development
12
Flooding
  • We tend to have a biased view of floods as
    unpredictable, disastrous events, while in
    reality they are predictable and necessary
    occurrences.
  • How does impervious surface affect the likelihood
    of flooding?

13
Flood probabilities
  • Recurrence interval
  • 1 in 100 year flood
  • probability of 0.01 or 1
  • Also referred to as the recurrence interval
  • Defined as P 1 / T, where
  • P Flood probability
  • T Recurrence interval

14
Human influence on floods
  • Rapid runoff into channelized streams increase
    flood frequency and enhance downstream peaks in
    flood hydrographs.

15
Sediment transport
16
Sediment transport
17
The transportation of materials
18
Erosion
19
Erosion in action
20
Deposition
  • Deposition resulting in multiple channels
  • Deposition within a single channel

21
Sediment deposition and current velocity
22
Sediment load increases with discharge
23
Variation in sediment transport
24
Landuse/seasonal affects on sediment delivery to
the Minnesota River
  • 2001 Minnesota River at St. Peter, MN daily
    average flow and tss samples (draft)

25
Longitudinal profile of a river
  • As discharge increases
  • Channel Width increases
  • Channel Depth increases
  • Mean velocity is stable
  • Bed Material size decreases
  • Slope decreases
  • Sediment storage increases
About PowerShow.com