NOVELTY - A mycobag comprises a burlap bag filled with a biodegradable material and inoculated with a saprophytic fungus.    USE - As a mycobag useful for filtering agricultural and urban water runoff containing a contaminant selected from silt, toxins, bacteria, coliform bacteria, Escherichia coli, viruses, protozoa, amoebas, industrial toxins, petroleum products, pesticides, fertilizers, nitrogenous compounds, phosphorus compounds, carbonaceous compounds, chemical pollutants, and/or heavy metals (claimed).    ADVANTAGE - The mycobag provides fungal components to accelerate the decomposition of biodegradable fabrics and other materials in sensitive environments; to enhance water retention properties of such materials, using the natural water-absorption properties of mycelium; and to help catalyze significant climate change in arid environments through the enhancement of the water retention capacities of the top soils, the net effects of which are erosion control, and significant enhancement of biological communities which then can become seed banks leading to a creations of satellite communities in proximity to the genome source. The fungally colonized mycelial fiber substrates liberate carbon dioxide, essential for healthy plant growth, especially essential for young seedlings. The adsorbent or absorbent biodegradable fiber cloths and mats inoculated with spores and/or hyphae of petroleum oil-eating fungi. Thus the oil slicks or spills may be soaked up by the cloth or mat material and digested by the mycelium of the fungus. The fungally impregnated biodegradable materials along stream and sensitive watersheds to ameliorate the impact of runoff containing sediment and pollutants. The method is use for bioremediate contaminated, toxic and hazardous sites, providing breakdown of dangerous organic, inorganic and biological threats while simultaneously triggering the ecosystem recovery. The colonized fiber substrates combats virulent bacteria, reduces or eliminate viruses, limit pathogenic fungi, yeasts, and molds, control protozoa such as amoebas, ciliates, flagellates, and sporozoans, controls multicellular organisms such as rotifers and trap and digest nematodes.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for filtering (P1) agricultural and urban water runoff containing a contaminant selected from silt, toxins, bacteria, coliform bacteria, Escherichia coli, viruses, protozoa, amoebas, industrial toxins, petroleum products, pesticides, fertilizers, nitrogenous compounds, phosphorus compounds, carbonaceous compounds, chemical pollutants, and/or heavy metals, involving treating the water runoff with a mycobag comprising a burlap sack filled with a biodegradable material and inoculated with a fungal inoculant of a saprophytic fungus, where the fungal inoculant is selected from spores, and/or mycelium, where the saprophytic fungus is selected from Pleurotus, Piptoporus, Fomitopsis, Trametes, Hypsizygus, Ganoderma, Inonotus, and polypore mushrooms, and where the burlap bag also contains plant seeds.