The Garhwal Himalaya is a majestic region in the Indian Himalayas located in Uttarakhand. The Havel, one of the most important spring-fed tributaries of the holy River Ganga in the Garhwal Himalaya, originates from the Chailusain mountain range in Pauri Garhwal. It sustains a wide variety of aquatic life, including a unique and diverse array of macrozoobenthic communities. Macrozoobenthos are the essential elements of freshwater ecosystems, as their sensitivity to pollution and habitat alternations makes them reliable bioindicators for monitoring the ecological balance as well as stream health. The present study has been conducted at two different sites (i.e. Mohanchatti between 30003’51’’ N Latitude and 78024’17’’ E Longitude, and Phoolchatti: between 30007’00’’ N latitude and 78022’38’’ E Longitude) to assess the various physicochemical parameters and macrozoobenthic communities in the Havel River. By analysing monthly physicochemical parameters as well as Macrozoobenthic density and diversity patterns, we assessed the impact of both natural disturbances (e.g., floods, droughts, and landslides) and anthropogenic activities (e.g., deforestation, pesticide use, pollution, tourism, and fishing) on the river ecosystem. These factors have contributed to a decline in the diversity and distribution of sensitive macrozoobenthic taxa (EPT: Ephemeroptera, Plecoptera, Trichoptera) and altered river dynamics, including reduced pH and alkalinity, increased water hardness, elevated TDS levels, etc. Ultimately, these changes have negatively affected the overall health of the river ecosystem. The findings emphasize the need for conserving diverse habitats and ensuring the ecological integrity of the river.