Murray Creek Watershed Stream Ecosystem Assessment
Introduction
Freshwater ecosystems, particularly those in valley bottoms and floodplains, play a crucial role in our environment. They're inherently valuable and vital for agriculture, resource management, natural habitats, and land development. These ecosystems are facing mounting challenges due to climate change and human activities. Therefore, thoughtful and accurate control of these areas ensures their health and productivity. These principles guide the efforts of the Murray Creek Watershed Stream Ecosystem Assessment. Our goal was to understand the state of the streams and freshwater ecosystems here, a mission that resonates strongly with the Nechako Environment Water Stewardship Society.
Our findings in this report provide a comprehensive view of Murray Creek Watershed's current conditions. This knowledge serves as a cornerstone for informed decision-making regarding this remarkable natural resource's stewardship and sustainable management.
The assessment has four main components:
1. Stream condition assessment
2. Beaver habitat suitability analysis
3. Identification of areas of interest
4. Planning of continuous monitoring
Murray Creek Watershed
Stream Condition Assessment
To gauge the health and present conditions of the Murray Creek watershed stream ecosystem, a comprehensive assessment was executed, considering vital controlling factors like hydrological, biological, and geomorphological aspects. Leveraging Maxar satellite imagery from 2021 and 2022 and utilizing the capabilities of QGIS, indicators within these categories, namely riparian vegetation, visible erosion, and depositional features such as point and mid-channel bars, were evaluated.
1. Optimal (High Quality)
Characteristics:
Vegetation Cover: Dense and diverse vegetation. Different layers of vegetation (trees, shrubs, and ground cover) are present.
Bank Stability: Banks are well-stabilized by root systems, with minimal erosion visible.
Functional Value: Provides ample shade, maintaining cooler water temperatures. Rich habitat that can support a diverse range of species.
Human Impact: Minimal to no human disturbance. There's a clear buffer between land use activities and the riparian zone.
2. Moderate (Medium Quality)
Characteristics:
Vegetation Cover: Moderate coverage
Bank Stability: There are some signs of erosion, but there are areas with stable banks due to vegetation.
Functional Value: Provides some shade, but not optimal. It offers habitat but might not support a wide range of species.
Human Impact: There is some evidence of human disturbance, but it's not severe. This might include occasional grazing, footpaths close to the water's edge, etc.
3. Degraded (Low Quality)
Characteristics:
Vegetation Cover: Sparse vegetation and lack of ground cover leading to exposed soils.
Bank Stability: Erosion evident; banks are bare with little root structure holding the soil.
Functional Value: Limited shade over water can lead to elevated water temperatures. There is little to no habitat provision for wildlife.
Human Impact: Signs of overgrazing, trampling, mowing up to the water's edge, construction, dumping, etc.
The riparian zones, vital for promoting bank cohesion, stabilizing stream temperatures, and offering habitat for aquatic life, were assessed based on their presence, absence, and connectivity within the ecosystem. The very essence of these zones delivers invaluable insights into the ecosystem's overall health and functionality.
Observable features indicative of a shift from biological to hydrological control include the augmentation of erosion and the deposition of fine sediment. Such deterioration encompasses the undercutting of stream banks, sediment accumulation in bars and the stream bed, and suspended sediment's impact on water quality. Employing high-resolution imaging techniques, and advanced satellite and drone imagery provided a detailed inventory of these conditions. The resulting data layers illustrated critical features like riparian zones, erosion areas, and depositional sites.
Optimal (High Quality): Accounting for 31.13 km, these stream segments showcased dense vegetation, with well-rooted banks indicating minimal erosion and the ecosystem's thriving state.
Moderate (Medium Quality): Covering 20.95 km, these sections displayed visible erosion but maintained some functionality regarding habitat provision and water temperature regulation.
Degraded (Low Quality): Spanning 23.07 km, areas under this category suffered from sparse vegetation, conspicuous erosion, and a marked human impact, signalling a pressing need for restoration.
Beaver Habitat Suitability Analysis
Beavers are influential ecosystem engineers in British Columbia, shaping freshwater ecosystems through dam construction. Their actions significantly impact hydrology, geomorphology, and ecology. Beaver dams slow water flow, reducing soil erosion and preserving bank stability. They act as natural water purifiers by preventing sedimentation.
Furthermore, beaver ponds serve as water reservoirs, storing water during abundance and releasing it slowly during dry periods, supporting aquatic life. Beavers also bolster floodplains by creating canals and saturating these areas, enhancing resilience to disturbances like wildfires, floods, and droughts.
To assess beaver habitat suitability in the Murray Creek Watershed, we surveyed dams and employed a machine-learning model developed by Landen Matechuk at Cedar Shore Consulting. This tool considers topographic, hydrological, and environmental data to calculate a suitability score from 0 to 1.
.jpg)
The results of the beaver habitat suitability analysis reveal promising findings for many sections of streams within the agricultural area of the Murray Creek Watershed. The assessment identified numerous locations suitable for beaver dams, indicating the potential for beaver dam analogs. These findings offer valuable insights into the ecosystem's capacity to support beaver populations and their critical dam-building activities. It also underscores the importance of recognizing these areas as potential sites for further conservation and restoration efforts, as they could significantly enhance freshwater ecosystems and their ecological services.
Areas of Interest
Following our comprehensive analysis, we have identified three specific areas within the agricultural belt of the Murray Creek watershed that exhibit significant potential for beaver dam analog restoration. These areas have been selected based on a dual criterion: high levels of suitability for beaver habitat, as determined by our advanced modelling, and the presence of degraded riparian zones. It's important to emphasize that these identified areas represent a unique confluence of ecological factors that make them prime candidates for restoration efforts. The synergy of favourable topographic conditions and habitat suitability in these selected zones provides an ideal foundation for establishing beaver dam analogs. Moreover, the presence of degraded riparian zones highlights the urgent need for ecological restoration and enhancement.
Continuous Monitoring
Continuous monitoring is essential for tracking shifts in our stream systems. We continue to explore the employment of advanced technologies like drones, satellite imagery, and strategically placed monitoring instruments to gather data. This information guides us in identifying areas requiring restoration and assessing ongoing projects' effectiveness.
Water sampling is another vital aspect of our monitoring process planning. It helps us determine the presence or absence of specific fish species, offering insights into biodiversity and ecological balance. This method highlights how habitat changes impact aquatic life, including beavers' influence.
Our continuous monitoring forms the basis of an adaptive management plan. Real-time data on restoration effects allows us to adjust techniques and strategies, ensuring efficient resource use. This iterative approach, driven by technology and data analysis, leads us toward more sustainable riverine ecosystems.
Conclusion
Understanding our stream ecosystems is urgent due to increasing pressures on freshwater ecosystems from climate change and land use. We focus on valley bottoms and floodplains, starting with the Murray Creek watershed. Our goal is a comprehensive report on the area's streams and freshwater ecosystems to inform protection, restoration, and sustainable land use. This knowledge isn't limited to Murray Creek; it can guide efforts in other regions, contributing to global discussions on sustainable freshwater ecosystems. Our research promotes environmental stewardship by balancing ecological integrity and human activities.