The Kayal area extends to Kandachira, Panayam, Kadavoor, Thrikadavoor, Anchalumood, Thevalli, Ashramam, and reaches the southern side of the KSRTC bus stand in Kollam.

[10] During the colonial era, the Dutch Naval Commander General D’ Lanoy is believed to have ordered the reclamation of part of Ashtamudi marshes on the southern flanks, particularly in Dalawapuram, for the plantation of coconut and other fruit trees.

Subsequently, in the nineteenth century, the British expanded the expanse of Quilon by establishing an army garrison and extending markets in the area.

Furthermore, the establishment of roads and a railway link between Kollam and Ernakulam via Munroe Island in 1958 eventually led to the fragmentation of the Ashtamudi estuary into two parts, particularly isolating the Karali marshes.

National Highway 47 (NH 47) passes through the lake periphery not only from Quilon but also to other locations on its bank from Thiruvananthapuram to the northern towns of Kerala.

From the east, the estuary comprises eight arms: Thevally, Kureepuzha, Kandachira, Thekkumbhagam, Peruman, Kanjirottu, Kallada, and Kumbaluthu, giving it the name "Ashtamudi" which means "eight-coned."

The central area of the estuary typically ranges in depth from 1 to 2 meters, featuring a deep, funnel-shaped depression along its eastern margins.

Littoral drift, which involves the movement of sediments in near-shore zones by waves and currents, significantly influences the shaping and orientation of coastal landforms and the overall evolution of the coast.

In natural conditions, high drift rates are likely to lead to the formation of shoals and bars at the mouth of the estuary, which may be periodically cut open by high-velocity river flows.

With the reduction in inflows from the Kallada River, the mouth of the estuary requires periodic dredging to maintain sufficient depth for port operations.

The coastal side of the basin exposes the Guruvayur Formation from the quaternary period, characterized by a sand-silt-clay admixture of marine origin.

Though it provides irrigation to 61630 ha for paddy and upland crops, it has aggravated the salinity ingress into the wetland and the river due to reduced outflows during summer months.

However, the decline in water quality within the estuary has been notable due to the continuous discharge of untreated waste from various sources, including Kollam City, tourist resorts, industrial units, slaughterhouses, and houseboats.

[17] This heritage site encompasses more than 50 hectares, including the Government Guest House complex, the mangrove area, and the creek of Ashtamudi Lake.

[3] The water body is the habitat for phytoplankton from the genera Amphora, Borosigma, Cyclotella, Cymbella, Gyrozigma, Meloziva, Navicula and Nitzschi.

Additionally, the lake serves as a nursery ground for commercially important shrimp species that are harvested off the Kollam coast.

It is also a congenial habitat for all species of penaeid and palaemonid Prawns, edible crabs, paphia malabarica (short neck Clams) and a variety of fish.

Ashtamudi yields an annual landing of 28,611 metric tons of biomass, based on five years of catch assessments conducted at five sites.

Among shellfish, Fenneropeanaeus indicus, Metapenaeus dobsoni, Macrobachium rosenbergii, Scylla tranquebarica, S. serrata, and Portunus pelagicus are dominant species in fish landing (Harikishnan, 2015).

The coir thus retted serves as a crucial input for cottage to medium-scale industries, producing ropes, mats, baskets, and wall hangings.

A variety of tourism packages are available, connecting all the backwater cities of Kerala, including Kollam, Alappuzha, Kumarakam, Kottayam, and Kochi.

Houseboats typically follow a specific navigation path, starting from the Kollam KSWTD boat jetty via National Waterway 3 to Munroe Island.

[23] This is a narrow patch of land popped up a few years ago in the Ashtamudi Lake about 350m away from the Sambranikodi coast and it became a complete isle after soil dredged for the construction of the national highway was dumped in the backwaters.

The prestigious President Trophy Boat Race (Vallam kali), held annually on November 1st in the Estuary, commemorating the day Kerala State was created, serves as a major attraction.

With numerous drainage channels from households and businesses flowing into the lake, local authorities have been directed to implement urgent remedial actions.Garbage covers many areas, including Link Road, Pullikada, Thoppil Kadav, and Manichithodu.

A recent study has revealed the extent of microplastic pollution in Ashtamudi Lake, a Ramsar wetland in Kollam district, highlighting the necessity for ongoing monitoring and addressing "potential public health concerns."

"Notably, the majority of particles were in the smaller size range, suggesting their potential bioavailability to aquatic organisms," the study noted.

Any decisions made concerning the Ashtamudi Estuary's resources and its sustainable management significance is dictated by about a million people who live on its shores and the large species of rare birds and animals which provide the equally important biodiversity to the lake's environs.

The accident involved the derailment of the Island Express train, which was traveling from Bangalore to Thiruvananthapuram, while it was crossing the Perumon bridge over Ashtamudi Lake.

There is a 1978 Indian Malayalam-language film Ashtamudikkaayal with Prem Nazir, Jayabharathi, Adoor Bhasi and Sreelatha Namboothiri in the lead roles.