Flowing in the open almost to the Grand Canal at Harold's Cross, its lower reaches, including multiple connected artificial channels, are almost entirely culverted.

Its volume was boosted by a drawing off from the much larger River Dodder, it powered multiple mills, including flour, paper and iron production facilities, from at least the 12th century until the 20th.

The flooding led both to the lack of a crypt at the cathedral and to the moving of the graves of satirist Dean Swift, author of Gulliver's Travels, and his friend Stella.

After a largely culverted stretch, its early open course, near Old Belgard Road and the former Jacob's Biscuit factory, has been straightened where it flows in what is now an area of light industrial development.

This channel, the first stretch of City Watercourse, carried water from the River Dodder extracted at Balrothery Weir in Firhouse; as of 2020, it has been dry for at least two decades.

[3] The Poddle's modest volume was boosted for over 700 years by a significant addition of water diverted from the River Dodder at a large weir at Balrothery in Firhouse, and carried by the three-kilometre first section of the City Watercourse.

After a mix of culverted and open sections, it reaches Sundrive Road in Crumlin, where a shopping centre was built on the site of another former mill, the Larkfield complex.

While the current "Stone Boat" is a modern replacement, it was formed based on the preceding structure (constructed in 1245), which lay in an open area called the Tongue-field; it is now on a suburban street.

[3] Emerging from the syphon under the Grand Canal, the river continues to bend northwest, passing the grounds of the former barracks, now Griffith College and going by the National Stadium.

After this it runs southeast, passing Pimlico, Ardee Street and the western end of the Coombe, again crossing the line of the Commons Water, and then turning almost 90 degrees at Warrenmount, a former convent, in the northern part of Blackpitts, where there was a large millpond and major mill, and a side millrace, and heading for its ancient course.

[3] Nowadays, much of the lowest course of the Poddle is in a large brick tunnel under the city streets and Dublin Castle,[3] and while access is restricted, it is of walkable scale and at least two writers on the river have been given tours of part of the route.

Following the civic inquisition, as it was called, a deal was made, in 1244–1245, with the Abbey of St Thomas, to use their Dodder-boosted Poddle supply for broader city purposes.

[3] Near the point where the abbey had diverted the Poddle, but a little further south, the flow was divided, and a new, city-owned channel, the City Watercourse, was formed, carrying the water towards the James' Street area, where a storage basin was built.

The Tongue or Stone Boat, dividing the flow 2:1, was agreed to be maintained, and the city was to pay for any related works required on the monastic weir on the Dodder.

Further, the officials of the city were allowed to gather citizens, and tenants of the religious settlements, to repair the weir, channels and dividing structure, and it is recorded that the Tongue was rebuilt in 1555.

In 1534, rebels following Silken Thomas broke the supply lines in an attempt to help his cause,[19] and in 1597 the Talbots of Templeogue blocked the flow in a dispute with mill-owners using its power, an act repeated by Royalist forces during the English Civil War to leave the Cromwellian forces occupying Dublin short of both water and milling capacity for food production.

[17] Reputedly a later landowner in Templeogue, Sir Compton Domville, threatened to do the same if a nephew convicted of murder was executed; the threat was not tested, as the aristocrat in question, Lord Henry Barry, had his sentence commuted to banishment.

[17] Even when no potable water was required from the Poddle, the city authorities were obliged to maintain a certain flow in the river for the benefit of industrial users such as mills and breweries, and a last modernisation of the Balrothery weir and sluice arrangements was made in the early 19th century.

[20] The Dodder-Poddle connection was disturbed by housing developments from the 1970s, and was allowed to dry out in the late 20th century; only a tiny part still carries water, though ample evidence of the watercourse can be seen: the sluices and channel on the north side of the Great Weir still stand.

[8] Mills and industrial facilities supported by the City Watercourses and Poddle included: The Poddle, and initially Dubh Linn too, naturally provided a water defence for the south and east faces of Dublin Castle, though its flow was not substantial enough to create a significant barrier, and a dam was built near the river's exit from the castle (giving the name to Dame Street),[22] to provide a greater depth of water.

This escape, O'Donnell's second,[24] is commemorated by an annual trek from central Dublin into the mountains since five people began it in 1954; as of 2017, 200 hikers are chosen from 800 or more applicants each year.

The church was elevated to collegiate status by John Comyn in 1191 and the early building of wood was remade in "hewn stone" and dedicated to "God, our Blessed Lady Mary and St Patrick" on 17 March of that year.

Historians have debated the choice of site, on marshy ground between two streams, and Bernard proposed that it could only be because of some holy association of the location, most probably with St Patrick.

[27] For centuries the Poddle, even as it was progressively culverted, caused regular flooding and dampness in the cathedral, as well as many other buildings in the Blackpitts and St Patrick's Street areas.

"[17] During the major reconstruction of the cathedral in the nineteenth century, the graves of Dean Jonathan Swift and Stella were moved to their present location, due to the problem of the Poddle.

[27] A statutory body, the Poddell Commission, was formed by an Act in the times of Charles II to manage city centre flooding from the river, especially if it might affect St Patrick's Cathedral.

[29] As of 1835, the commission's membership included many of the most senior officials of both Dublin and Ireland, including both the Lord Mayor and the Recorder of Dublin, the Church of Ireland Archbishop of Dublin, the Deans of both St Patrick's and Christ Church Cathedrals, the Lord Chief Justice, the Chief Justice of Common Pleas, the Principal Secretary of State for Ireland, the Attorney and Solicitor-General, and the Earl of Meath, along with later-added diocesan officials, the Chancellor of St Patrick's Cathedral and the Lord of the Manors of St Thomas Court and Donore, while the Secretary of State was replaced by the Keeper of the Privy Seal.

Following public consultation in 2014, design work was due, as of 2016, on a plan focused on excess water storage options, primarily at Tymon Park, and the use of flood walls.

[13] The river, due to limited flow, long-term issues with pollution, and barriers at the Liffey end, and the syphon under the Grand Canal, has no significant persistent fish population, and also lacked sensitive invertebrate species.

[2] The Poddle is also referenced briefly in James Joyce's Ulysses,[36] and makes multiple appearances in his Finnegans Wake, which touches on its role in the city's water supply.