Anthropogenic activities in river catchments and hydromodification in the channel's morphology impact the ecology/ climate, resulting in catastrophic flooding. Structural measures using cement concrete are employed without efficient flood risk assessment, resulting in additional environmental damages as cement concrete is considered the third biggest emitter of CO2 globally (7-10%) after power generation and aviation/ transportation industries. The researchers always endeavoured to dispose of substantial waste exhibiting pozzolanic properties from diverse industrial/ agricultural fields and the construction industry to formulate greener supplementary cementitious composites (SCMs). The incorporation of fibres obtained from the waste materials had been envisaged as an inexpensive solution to overcome the weak tensile/ flexural strength of binders for lesser reinforcement stipulations for mitigation against rupture before the initiation of plastic deformation. As a solution, non-cement alternative, lime-based fibre-reinforced pozzolanic, innovative composites (NALFRIC) (low - medium strength requirements of 10-30 MPa), fibre-reinforced partial cement-based SCMs (medium - high-strength SCMs 50-70 MPa), and novel, alternative fibre reinforced iron-based composites (NAFRIC) (high-strength SCMs 50-70 MPa) were developed in this research project as sustainable, eco-friendly greener materials. NAFRIC contains iron powder, pozzolans, limestone and fibres, which was anticipated to attain a lower CO2 equilibrium as it absorbs CO2 from the environment to produce ferrous carbonate (FeCO3), yielding a rock-like sustainable performance to drying/ setting. The durability study using concentrated sulphate solution of 2.5% Na2SO4 + 2.5% MgSO4 and chemical-mechanical synthesis/ micro-structural studies using advanced XRD/ SEM/ TEM/ EDX testing supported the findings about the developed composites as sustainable/ eco-friendly. These materials demonstrated up to 50% lower embodied CO2 with up to 25% lower cost and are considered suitable for all types of applications/ strength stipulations in the construction industry, especially in megaprojects, marine environments, and water channel stabilisation/ hydromodifications.