While hydrologic, biological, and geomorphic processes in headwaters have seen much study in the past 50 years, the role that headwaters play within the watershed, and the link to downstream systems, are nevertheless poorly understood.  We know that they are critical areas for nutrient dynamics and serve as a habitat for fish, amphibians, and macroinvertibrates.  Due to geographic isolation headwater systems can also support species that are isolated genetically.  As such, they contribute to biodiversity in an important way.  Inextricably linked, they are pivotal for understanding sedimentology and hydrology, and for protecting ecosystems downstream.  Human activity can have a negative impact on headwaters, and can compromise slope stability.  Small but numerous, the role that they play are nevertheless frequently underestimated, and managed far worse in comparison to their larger counterparts downstream.  According to Benda et al (2005), they comprise 60-80 percent of the cumulative length of the drainage network, so it is imperative that proper management in headwater areas is approached seriously and further studied (p. 835). 

             There is no universally accepted definition: headwater systems are essentially the areas from which water originates within a channel network, characterized by interactions among hydrologic, geomorphic, and biological processes that differ from hillslopes to stream channels and from aquatic to terrestrial environments (Gomi et al, 2002, p. 905).  They can be found in mountain meadows and lowland basins, but primarily study is focused on the steepest portions of channel networks in mountainous regions.  In terms of hydrology and geomorphology, headwater streams are divided into four regions: hillslopes, zero-order basins, transitional channels between zero-order basins and first-order streams, and first- and second-order streams.  Hillslopes have either divergent or straight contour lines, usually with no channelized flow.  Zero-order basins are unchanneled and intermittent swales with convergent contour lines; “bedrock hollows,” steep swales in which shallow rapid landslides frequently occur, are a major initiation point for debris flows in low order streams (Benda et al, 2005, p. 837).  Colluvial material typically fills such hollows.  Between the unchanneled swales and first-order streams are transition zones referred to as “channel heads,” when channels with defined banks emerge from the basins.  Typically a seepage point or area which produces flow during storm periods, they represent the headmost discernable channels with temporary or ephemeral flow.  Temporary channels have roughly a minimum of four to five months continuous flow in an average year, whereas ephemeral channels flow only for a few days during wet periods.  First-order channels are the uppermost unbranched streams with either persistent flow or a sustained intermittent flow.  Second-order, single or multiple branched streams can also be considered headwater streams, depending on the degree of coupling between hillslopes and channels (Gomi et al, 2002, p. 908).  This project will take a brief look at headwaters in BC; the extent to which they cover our landscape, the services they provide, and how we can better manage them.