The porous lava of Reykjanes peninsula means there are no rivers on the surface but around Reykjavik and Mt. Esja there are quite a few, some of them great salmon rivers. One of the good ones flows right through Reykjavik and even though it's within the city limits it has great natural surroundungs. These rivers are nothing compared to the size of the monsterous glacier rivers of the country but they make up the size difference in great diversity and there's a lot of nice rapids and waterfalls in many of those rivers.