Digital resources on the commons

"General map which shows the status of the mother river Queiles from the Kingdom of Aragon until it enters the terms of Tudela, the dams, main ditches, Bracers highest grade, which includes the villages with their jurisdictions and roads", drawn March 15, 1792 by Fernando Martínez Corcín. Source: Archivo general de Navarra, Cartografia, signature 146.
(from the ICA page on the Albalá de Tudela)

Rechtsgeschiedenis Blog recently covered digital resources on commons institutions, highlighting the website of Institutions for Collective Action, the Digital Resources on the Commons page of the International Association for the Study of the Commons, and Indiana University's Digital Library of the Commons. There's a tremendous amount of historical material, both primary and secondary, available through these sites.

Like Otto at RB, I'm particularly interested in the water institutions. Institutions for Collective Actions's portal has case studies for 5 Dutch and 3 Spanish waterboards, with a tremendous amount of information on the historic legal institutions governing the management of water in these areas. For instance, here's an excerpt from a description of how the waters of the River Queiles around Tudela, in Navarre (in the north of today's Spain) were governed under a series of ordinances going back to 1220 (a hundred years after the city's Muslim rulers were ejected, but obviously showing the continued influence of their rule):

The ownership of the water of the river Queiles was divided into monthly shifts between the communities that were entitled to irrigation. The first description of this system is to be found in the ordinances of Tudela of 1220. Each month was divided into three periods of different lengths: the almoceda, the alhema. and the entremés. The almoceda began at sunrise on the 22nd of each month and ended on the 26th, lasting four days and nights. The alhema began at sunrise on the 26th and was of variable duration, depending on the location and the time of year: on the right bank, it lasted five days in ten of the twelve months of the year and four days in April and May. From 1376 onwards, on the left bank the alhema lasted for eight days and nights, except in April and May, when its duration was reduced to seven days. The remainder, between the end of the alhema and the start of the almoceda was called entremés.

During the almoceda the river was divided into two parts, flowing through the ditches Naón (on the left bank of the river) and Mendienique (on the right bank), to irrigate the fields of the villages situated on both banks of the river. On the left, Monteagudo received half of this flow and the other half of this flow was destined for Cascante and Urzante, downstream. On the right bank, the ditch Mendienique distributed half of the flow to Malón, provided a fila (approx. 12 liters per second) of water to the Tulebras Monastery, while the remainder of this flow continued to Barillas and Ablitas. During this period, entitled irrigators were forbidden to either impound water, waste it, or donate it to others, because the overflow caused by rain (which became known as "aguas sobradas") belonged to the city of Tudela.

The city of Tudela, at the mouth of the river, was the sole owner of river water during the alhema. In that period, water diversion ditches were closed (abatimiento), only leaving a minimum flow, regulated according to the cases in a teja (a flow of about 3 liters per second) and half a fila (a fila equalling a flow of  12 liters per second), so that all the water ahould reache the fields of Tudela. However, before reaching the end of Tudela territory, three so-called sesmos, flows of two filas ( about 24 liters per second) of water, were deviated from the main flow to irrigate the fields Murchante, Campoadentro, and Cardete.

During the entremés, being the monthly time period between the end of the alhema and the start of the almoceda, water use was open to all villages in the basin, according to shifts likewise established. The water in the ditch Calchetés on the left bank of the river, was seized by Novallas and Monteagudo, in shifts of three and two days respectively. The water running through the ditch Naón was distributed in shifts of four days between Monteagudo, Tulebras, and Cascante. On the left bank, the village of Malón had the use of the water from the ditch Mendienique for five days, Barillas for four days, Ablitas having the use of the water for the remaining eleven days. The use of excess flow caused by rain (“aguas sobradas”) was the privilege of the city of Tudela.