Principles of River Ecology

New Mexico Watershed Watch Teacher TrainingSeptember 2004

by Richard Schrader

River Ecology: Connecting Science with

CommunitiesPhysics: Streamflow, Channel Morphology, Sediment/ErosionChemistry: pH, Nutrients, MineralsBiology: Insects, fish, riparian habitatSocial science: Land use, laws, policies and need for collaboration

What is a Watershed? A drainage area to which water flows to a stream, lake, or to the ocean that is separated from other

watersheds by ridges and peaks.

What Happens Upstream Affects Conditions

Downstream

We often are concerned about how the actions of people upstream have an impact on us.Do we think often enough about how our actions affect people downstream of us? Student awareness of river ecology conditions becomes the starting point for caring to take action

Stream Order

Helps us characterize steepness of streams, channel size, water flow, and ecology.1st order: where a stream first flows year-round permanently.2nd order: where two 1st order streams connect.

River Continuum

Concept (RCC, by Vannote)

Model that predicts how rivers change as they move downstream.

RCC explains how physical aspects and biological aspects relate.

Physical changes: Water velocity, channel shape, light

Chemical changes: pH, TDS, Turbidity, Nutrients

Biological changes: Primary production, benthic insects

Physical ChangesWater velocity & substrate: Speed of water shapes habitat. Steep streams in headwaters keep creek clear of sediment. Low gradient streams become sandy and muddy. This affects substrate character by affecting embeddedness at the bottom of stream. Organisms must be adapted currents or their population declines.

Physical Changes (continued)

Channel shape: Headwater streams are narrow and less sinuous. Low elevation streams become sinuous and wide as they pick up sediment and flattens out. Light: Narrow streams in the 1st to 2nd order streams means plants typically shade the water nearly completely. Higher order streams (3rd and higher) have less shading. This affects photosynthesis and food sources for insects.

Chemical ChangespH: High elevation streams tend to be more acidic if they start in granite-derived soils. pH becomes more basic in lower elevations. All NM streams tend to be basic due to lots of limestone geology.

TDS (Total Dissolved Solids): Streams accumulate dissolved minerals (mostly calcium carbonate) as they travel downstream. Undeveloped high elevation streams may have 160 microsiemens. Rio Grande in Albuquerque may have 414 + microsiemens.

Chemical Changes (continued)

Turbidity: High elevation streams with little disturbance often have clear water. Low elevation streams are often muddy which reduces algae production. Poor land use practices increase turbidity. Clarity of water improves with good vegetation cover.

Chemical Changes (continued)

Nutrients: Nitrogen & Phosphorus concentrations are typically low at high elevations. Concentrations increase in higher order streams. Natural sources of nutrients include fires and spring runoff.

Human-caused sources include livestock, logging, wastewater treatment plants.

Biological Changes: Primary production

Primary production (photosynthesis) vs. respiration (removal of oxygen) changes -- High elevation streams shaded so much that primary production is low. -- Mid-elevation streams have more light and higher temperatures. Primary production greater than respiration. -- Low-elevation streams have low primary production and dying phytoplankton which means primary production is less than respiration.

Biological Changes: Aquatic organisms

High elevation streams: Benthic insects that collect and shred leaves dominate (80% of total). Various minnows, trout, sculpins.

Mid-elevation streams: Grazing insects increase while shredders decrease. Most productive section of the continuum for bugs and fish. Fish that can tolerate wide temperature ranges daily and seasonally such as trout, and many minnows, and suckers.

Low-elevation streams: Filtering and gathering insects dominate (85%). Suckers, carp, chub, fish that feed on plankton, mollusks and an occasional invertebrate.

Clean Water Act & Water Quality Standards

Key Components1. Designated Uses of the

River2. Water Quality Criteria -

Tribal and state criteria.Note: River Source has several new teaching activities

helping students understand the laws for Water Quality & Water Quantity and how to get involved in protecting

watersheds.

Designated Uses

Designated Uses for NM include: Fisheries (high quality coldwater to warmwater), primary & secondary contact, livestock watering, irrigation & wildlife habitatWhat can you and your students do?

Document how the river is really being used and petition for changes at the Water Quality Control Commission.

Water Quality CriteriaNumeric and qualitative criteria set to protect designated uses

RIO GRANDE BASIN - The Jemez river and all its tributaries above state highway 4 near the town of Jemez Springs, and the Guadalupe river and all its tributaries.

A. Designated Uses: domestic water supply, fish culture, high quality coldwater fishery, irrigation, livestock watering, wildlife habitat, and secondary contact.

B. Standards:(1) In any single sample: conductivity shall not exceed 400 µmhos, pH shall be within the range of 6.6 to 8.8,

temperature shall not exceed 20°C (68°F), and turbidity shall not exceed 25 NTU. The use-specific numeric standards set forth in 20.6.4.900 NMAC are applicable to the designated uses listed above in Subsection A of this section.

What can you do? See if the criteria are being met. Send data

to River Source and present data to Water Quality Control Commission.

Look at Rivers as a Whole

Look both at what is happening upstream and how you affect conditions downstream.Changes in river conditions occur naturally but also are impacted by humans – the challenge is separating out human influences. Getting students hands involved in learning about conditions may get them to care about the river and see themselves as part of the whole.