Heavy rain brought travel disruption and flooding to large swathes of Scotland today.

The downpours also sparked new fears that homes could be flooded in Renfrewshire amid concerns that a dam could burst.

Commuters faced disruption after the heavy rainfall caused "severe" problems on the roads, and affected rail routes.

The Scottish Environment Protection Agency (SEPA) said there was one severe flood warning and six flood warnings in place across Scotland.

Motorists were told to expect lengthy delays and urged to drive with extra care.

The A720 Edinburgh City bypass was closed westbound from Straiton to Dreghorn junctions and was reduced to one lane eastbound at Dreghorn Junction.

Four other roads in Edinburgh were closed in both directions.

In the Borders the A72 Galashiels to Peebles road was closed between Clovenfords and Walkerburn due to a landslip.

Inspector Jill Kerr, of Lothian and Borders Police, said: "Thankfully weather reports suggest the worst rainfall is over and we expect flooding to subside over the next 12 hours.

"However the heavy rainfall over night has caused some severe problems on our roads."

Train services between Edinburgh and Glasgow Queen Street and from North Berwick to the Scottish capital were also disrupted, with passengers warned to expect cancellations and delays.

A major factor in the rail delays near the capital was the flooding of the tunnel linking Edinburgh's Waverley and Haymarket stations, which at one stage was under 2ft of water.

Routes from Bathgate to Newcraighall and Newcraighall to Dunblane were also affected.

Network Rail said that services will begin to return to normal as the flooding subsides.

In Renfrewshire a dam which was at risk of bursting earlier this week was again under pressure due to the heavy rain.

Heavy rain over the weekend affected the structural integrity of the dam at the reservoir known as Maich Fishery near Lochwinnoch in Renfrewshire.

Around 20 nearby households were today warned for a second time that they may have to be evacuated and some moved out themselves after warnings from police.

Some had left their homes earlier in the week after being warned of the danger.

The fire service was working with Renfrewshire Council to prevent the collapse of the dam.

Seven pumps were being used to pump water out of the reservoir today.

Strathclyde Fire and Rescue's high volume pump and four commercial pumps have been in place since the weekend.

Today they were boosted by two more commercial pumps, while Lothian and Borders Fire and Rescue Service's high volume pump was also brought in to help.

Sandbags were placed at the Maich Water inflow into the reservoir and work continued to divert the burn water.

The fire service said that around 20 properties down hill of the reservoir could be seriously affected should the dam give way.

A fire service spokesman said: "Torrential rain last night once more raised the water level in the Maich Water fisheries reservoir to a critical level.

"SFR and council staff have been working round the clock to ease pressure on the dam by reducing the water level and preventing water getting into the reservoir."

The most severe flooding in central Edinburgh occurred in the Princes Street Gardens area, where pumps were operating to bring the water level down.

The A760 between Lochwinnoch and Kilbirnie was closed because of the flooding risk.

SEPA issued a severe flood warning for the River Tyne at Haddington, and six flood warnings including one for the Water of Leith, which runs through Edinburgh, and two stretches of the River Earn in Perthshire.

It said that 13 flood watches were in force across the country from Angus and Fife to Dumfries and Galloway.

The Met Office issued a severe weather warning of heavy rain for Strathclyde, Central Scotland, Tayside and Fife.

It said that outbreaks of rain will be locally very heavy at times giving accumulations of 15 to 20 mm in places.

Lothian and Borders Fire and Rescue was called to the scene at around 8am and firefighters were using portable pumps to pump water out of the houses.

It was not known whether the residents had to leave their homes.

The fire service said water levels in the burn were now receding.